A Lump After Re2O or Re2O Fine (hADM ECM skin booster) : Why Diagnosis Must Come Before Dissolving Treatment

RE2O NODULE ASSESSMENT

A Lump After Re2O or Re2O Fine: Why Diagnosis Must Come Before Dissolving Treatment

Written by M.D. Bo Won Lee, Director of Springday Clinic Sinchon, Seoul.

Three-line overview

Not every palpable lump after an injection is a granuloma.

Re2O products are particulate human acellular dermal matrix products, not standard hyaluronic acid fillers.

Observation, antibiotics, intralesional therapy, biopsy, and surgery apply to different clinical phenotypes.

Evidence limitation: No publicly available product-specific guideline or comparative clinical trial establishing a standard treatment protocol for Re2O or Re2O Fine nodules was identified. Management must therefore be individualized, and parts of the treatment discussion are extrapolated from literature on other non-HA injectable materials.

Product

Particulate human acellular dermal matrix derived from skin tissue.

First decision

Determine whether the lesion is a deposit, infection, sterile inflammation, granuloma, or fibrosis.

Key caution

Hyaluronidase should not be presented as a direct antidote for the hADM particles.

The First Question Is Not “How Do We Dissolve It?”

A patient may notice a small bead, plaque, or firm lump after a Re2O procedure. The most useful first questions are when it appeared, whether it is shrinking or enlarging, and whether redness, heat, tenderness, drainage, or systemic symptoms are present.

Core principle: A lump is a physical finding, not a complete diagnosis.

What Are Re2O and Re2O Fine?

According to the manufacturer’s official product information, Re2O and Re2O Fine are particulate human acellular dermal matrix products derived from skin tissue. Re2O is listed as a 150 mg product, whereas Re2O Fine is listed as a 50 mg product with a finer particle profile.

Re2O

150 mg
Particulate acellular dermal matrix

Re2O Fine

50 mg
Finer particulate acellular dermal matrix

A smaller particle profile does not prove that nodule formation cannot occur. No direct comparative nodule-incidence study between the two products was identified. Results may vary with the anatomical site, skin thickness, injection plane, local volume, distribution, prior injectables, infection, and individual tissue response.

Why Hyaluronidase Is Not a Universal Solution

Hyaluronidase enzymatically degrades hyaluronic acid. Re2O products are not standard cross-linked HA fillers, so hyaluronidase should not be described as an agent that directly dissolves their hADM particles.

Hyaluronidase may still be relevant when a previous HA filler is present in the same area or when ultrasound identifies a separate HA deposit. In that setting, it targets the HA component rather than the dermal-matrix particles.

Four Clinical Patterns to Consider

1. Early Non-Inflammatory Deposit or Edema

A lump that appears immediately after treatment and gradually becomes smaller or softer, without redness, warmth, or increasing pain, may represent edema, bruising, superficial deposition, or localized clustering of material.

2. Infection or Abscess

Progressive erythema, warmth, tenderness, rapid swelling, fluctuance, drainage, fever, or spreading inflammation requires prompt assessment. Ultrasound, aspiration, culture, antibiotics, and drainage may be required depending on the findings.

3. Sterile Inflammatory Nodule or Foreign-Body Granuloma

A delayed firm lesion, recurrent swelling, or multiple inflammatory nodules without a confirmed infection may represent a sterile inflammatory or foreign-body response. Intralesional corticosteroid, corticosteroid combined with 5-fluorouracil, biopsy, or other interventions may be considered after infection has been reasonably excluded.

Evidence for these treatments comes mainly from other injectable materials. Current evidence does not support a definitive Re2O-specific dose or treatment interval.

4. Fibrotic or Encapsulated Lesion

A long-standing, fixed, nonfluctuant lesion with little active inflammation may be predominantly fibrotic. Repeated blind injections and aggressive manipulation may provide limited benefit and may increase tissue trauma.

When Ultrasound Adds Value

High-frequency ultrasound can help localize the lesion, assess fluid collections, identify prior filler deposits, characterize fibrosis, and guide targeted treatment. Doppler imaging may help evaluate inflammatory vascularity and the relationship to adjacent vessels.

Ultrasound cannot replace histopathology in every atypical case, but it can reduce guesswork before intralesional treatment.

Comparison Cards

Observation May Be Reasonable

Present from the early post-treatment period

Becoming smaller or softer

No progressive erythema or warmth

Minimal or no pain

Prompt Medical Review

Increasing size or tenderness

Redness, heat, or drainage

Fluctuance or rapid swelling

Fever or spreading inflammation

Further Diagnostic Workup

Delayed onset after an initially quiet period

Multiple or recurrent nodules

Very firm or fixed lesion

Poor response to initial management

A Stepwise Management Framework

Step 1: Document and Reassess

Record the exact product, treatment date, anatomical site, prior injectables, onset of the lump, and interval change. Standardized photographs and measurements are preferable to relying on memory.

Step 2: Exclude Urgent Conditions

Progressive pain, skin-color change, pustular drainage, fluctuance, systemic illness, or visual symptoms require prompt evaluation for infection, vascular injury, or another urgent complication.

Step 3: Manage Suspected Infection

When feasible, image and aspirate a fluid collection before antibiotics. Culture-directed antimicrobial treatment is preferred when a specimen is available. An abscess may require drainage. Intralesional corticosteroid should generally be deferred while clinically meaningful infection remains possible.

Step 4: Consider Intralesional Treatment for Sterile Inflammatory Disease

After infection has been reasonably excluded, intralesional corticosteroid may be considered. A 5-fluorouracil combination is used in some resistant granulomatous filler reactions, but this is not a product-specific Re2O protocol.

Thin-skin warning: Periorbital, forehead, and perioral treatment requires particular caution because intralesional corticosteroid can cause atrophy, telangiectasia, pigment change, or contour depression.

Step 5: Biopsy or Excision for Atypical or Refractory Lesions

Biopsy may be appropriate for progressive, ulcerated, draining, atypical, or treatment-resistant lesions. Surgical excision may be necessary for a localized refractory mass, but potential scarring, contour change, nerve or vascular injury, and incomplete removal should be discussed.

Treatments That Should Not Be Used Automatically

• Repeated hyaluronidase without evidence of an HA component
• Aggressive massage of a painful, red, or warm lesion
• Intralesional steroid before meaningful infection has been assessed
• Energy-based treatment presented as a proven method of dissolving hADM particles
• Additional filler or booster injection into an unresolved lesion

Checklist Before Treatment

□ Exact product and treatment date

□ Lot information if available

□ Onset and interval change

□ Previous HA or biostimulatory injectables

□ Redness, warmth, tenderness, drainage, or fever

□ Autoimmune disease or immunosuppressive medication

□ Ultrasound, culture, or biopsy requirement

□ Risks of atrophy, scarring, and contour change

Suitable and Less Suitable Candidates for Observation

Observation May Be Suitable

The lesion is clearly improving

No inflammatory or systemic symptoms

No concerning skin-color change

Reliable follow-up is available

Observation Alone Is Less Suitable

The lesion is enlarging or becoming painful

Redness, warmth, drainage, or fever

Delayed multiple nodules

Immunosuppression or recurrent infection

Frequently Asked Questions

1. Is every lump after treatment a true nodule?

No. Early edema, bruising, superficial deposition, and localized clustering can all feel nodular. A lesion that steadily becomes smaller and has no redness, warmth, or increasing pain may be observed. A persistent, enlarging, delayed, or inflammatory lesion requires medical assessment.

2. Can hyaluronidase dissolve Re2O?

Hyaluronidase is not a standard antidote for the hADM particles. It primarily degrades hyaluronic acid. It may be relevant if a previous HA filler is present in the same area. It should not be presented as a direct dissolving treatment for the Re2O matrix itself.

3. Should I massage the lump at home?

Aggressive massage is not recommended. A clinician may occasionally advise gentle early redistribution for a clearly non-inflammatory superficial irregularity. Redness, heat, pain, or suspected fluid collection requires assessment rather than manipulation. No validated universal Re2O massage schedule was identified.

4. Is ultrasound always necessary?

Not for every transient early bump. Ultrasound becomes more useful when the lesion persists, the injected material is uncertain, previous filler is present, or an intralesional procedure is planned. It can assess depth, fluid, fibrosis, and nearby vessels. Biopsy or culture may still be required in atypical cases.

5. Which symptoms suggest infection?

Progressive redness, warmth, tenderness, rapid swelling, fluctuance, drainage, fever, or spreading inflammation are concerning. Prompt in-person assessment is appropriate. Aspiration and culture may be considered when fluid is present. Intralesional corticosteroid should generally be deferred while infection remains clinically plausible.

6. How are sterile inflammatory nodules treated?

After infection has been reasonably excluded, intralesional corticosteroid may be considered. A corticosteroid and 5-fluorouracil combination is used in some resistant filler granulomas. Thin skin requires particular caution because atrophy and contour depression can occur. No product-specific Re2O dose or interval has been established.

7. How long does resolution take?

This cannot be predicted from the product name alone. Edema or an early deposit may gradually improve, whereas fibrosis or granulomatous inflammation may require repeated treatment and prolonged follow-up. The direction of change is more informative than a fixed deadline. Serial photographs and ultrasound can help document response.

8. Is Re2O Fine free from nodule risk?

No definitive conclusion can be made. Re2O Fine is described as a finer 50 mg product, but no direct comparative nodule-incidence study was identified. Particle characteristics are only one part of the risk profile. Skin thickness, injection plane, local volume, infection, and individual biology also matter.

9. Can another treatment be injected over the lump?

Additional injection into an unresolved lesion is generally not the first choice. It may obscure the original material and make later diagnosis more difficult. The area should be clinically stable and the cause of the lump clarified before further treatment is considered. This cannot be determined without an in-person assessment.

10. What should I look for in a complication clinic?

The clinic should distinguish infection, deposition, granulomatous inflammation, and fibrosis rather than treating every lump the same way. Ultrasound or an appropriate referral pathway, culture and drainage capability, biopsy referral, and structured follow-up are valuable. Avoid claims that one dissolving injection will solve every case. The risks of atrophy, scarring, and incomplete resolution should be explained.

References

1. L&C Bio. Official product information for Re2O, particulate human acellular dermal matrix, 150 mg.
2. L&C Bio. Official product information for Re2O Fine, finer particulate human acellular dermal matrix, 50 mg.
3. Chiang J, Liao YH. Mapping Filler Nodules. Dermatol Surg. 2026. DOI: 10.1097/DSS.0000000000004963. PMID: 41677155.
4. WFUMB Position Paper: Consensus on Best Practice in Aesthetic Dermatologic Ultrasound. DOI: 10.1016/j.ultrasmedbio.2025.07.003. PMID: 40866164.
5. Mlosek RK, et al. High-frequency ultrasonography for palpable nodules after dermal fillers. DOI: 10.15557/JoU.2020.0044. PMID: 33500791.
6. Kroumpouzos G, Treacy P. Hyaluronidase for Dermal Filler Complications. DOI: 10.2196/50403. PMID: 38231537.
7. Flores Rodríguez JC, et al. Management of PLLA Nodules. DOI: 10.7759/cureus.110742. PMID: 42438624.
8. Sivam S, et al. Giant PMMA Foreign Body Granulomas with Imaging. DOI: 10.4103/JCAS.JCAS_194_20. PMID: 38189071.

Final note
Results may vary. Evidence remains limited for product-specific Re2O nodule management. A persistent or inflammatory lesion requires a diagnosis-based plan rather than an automatic dissolving injection.

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