Re2O Side Effects: Is a Lump at 1 Week Normal?

Firmness you can feel for a few days after Re2O is usually a reaction you can watch for up to a week. With a related injectable from the same family, swelling and pain settled within one week. If one spot still stands out after a week, or it grows, turns red or hurts, that’s when to have it checked.

So the day 7 check is the turning point. In this article, we’ll cover how to tell swelling from a lump by touch, how often these reactions show up, the signs that can’t wait, and what to mention before treatment.

Quick summary

• Firmness, swelling and soreness after Re2O usually ease within about a week, so how the spot feels at day 7 decides your next step.

• Rule of thumb: even firmness that’s shrinking can be watched, while a single spot that grows or turns red and sore needs a visit.

• In a study of 20 people with Re2O in one cheek, there were no serious side effects over 20 weeks, but later reactions weren’t studied.

• Skin turning white near the injection site is a blood-vessel warning sign that needs care right away, whatever the day.

Re2O Lump After Injection: Can You Wait a Week?

If the treated area feels evenly firm and is shrinking along with the swelling, you can watch it for up to a week. Re2O is an injectable made from human skin tissue with the cells removed and ground into fine particles (an acellular dermal matrix*), so the spots where particles sit are easy to feel right after treatment.

*Acellular dermal matrix: the supportive framework of skin, mostly collagen, that’s left after the cells are removed.

In a study where Re2O (sold as Elravie Re2O) was injected into one cheek of 20 people, the only reactions were brief redness and slight swelling, and these settled without treatment. It was a small study that followed people for 20 weeks, so reactions that might appear later weren’t assessed.

Take a photo of the area in the same light on the day of treatment, day 3 and day 7, and gauge its size with your fingertip. Whether it’s shrinking or growing tells you more than any single number.

Re2O Nodule or Swelling: How Do They Feel Different?

Swelling spreads out around the injection point and feels puffy, and its edges blur as it shrinks over a few days. A nodule is a single spot you can pick out clearly, like a small bead, and it stays put after the swelling goes down.

Here’s how the two usually compare under your fingertips:

Particle-based injectables don’t compress as easily as soft gels, so a related product from the same family was injected with a thicker needle. That can mean a bit more pain and swelling right after treatment, which is part of why early firmness is common.

How Common Are Re2O Side Effects Like Swelling and Firmness?

There’s no large study on Re2O itself yet, so the closest reference is a related product: a different dermal matrix made from pig skin. Among 86 people who had it injected into their smile lines, 45.4% had swelling within 30 days. That swelling and pain settled within one week with simple care such as pain relievers and warm compresses.

Hardness or lumps showed no clear difference between that product and the collagen filler it was compared with. Swelling and pain were more frequent with the dermal matrix product, but they were mild and short-lived. Because these numbers come from a different product, they don’t carry over to Re2O directly.

For more on what is and isn’t known yet about this product, see our overview of Re2O safety and its limits.

Re2O Side Effects That Need Care Right Away

Blocking a blood vessel during a facial injection is rarely reported. The chance is low, but when it happens the effects can be serious and long-lasting*. The list below comes from guidance on dermal fillers, and it applies to Re2O as well because it’s injected into the face with a needle.

*Based on US FDA guidance on dermal fillers in general, not on Re2O specifically.

• Skin near the injection site turning white, gray or blue, or unusual pain: get medical care right away

• Changes in your vision: go to the nearest emergency room

• Sudden difficulty speaking, numbness or weakness in the face, arms or legs, difficulty walking, face drooping, severe headache, dizziness or confusion: go to the nearest emergency room

A lump that appears weeks or months later and keeps growing also needs a visit rather than waiting. Depending on the cause, it may need injections, oral antibiotics or removal. And if swelling worsens or spreads instead of fading, contact your provider right away.

What Should You Tell Your Provider Before Re2O?

If you have a breakout or rash where you’d be treated, it’s better to wait until it clears. Postpone treatment, or bring it up at your consultation first, if any of these apply:

• Inflammation or infection where you’d be injected, such as acne, a rash or hives

• A bleeding disorder

• A history of severe allergic reactions

• An allergy to numbing medicine such as lidocaine, or to animal-derived ingredients

• You’re pregnant or breastfeeding

In the Re2O study, lidocaine was mixed into the injection. You can ask at your consultation what will actually be mixed into yours.

Fitting Re2O Into Your Travel Schedule in Korea

Unless you’ve had sedation that day, there’s no need to postpone your flight home after Re2O.

It also helps to know what one visit means. Some treatments, like filler, change your shape the same day. Re2O works more gradually, so a single visit tends to bring a slow shift rather than a sudden change, and it doesn’t replace a full series if one was planned.

Day 7 often falls after you’ve flown home, so plan to do that check yourself. You can send a day-7 photo through the consultation button on this page. We can’t promise a reply time or remote care, so if the spot is red, hot or painful, or you notice any of the warning signs above, see a local doctor first.

The Bottom Line: Check the Spot on Day 7

At day 7, if the treated area is shrinking evenly, keep watching. If one spot remains, check its size and whether it hurts. If it’s getting smaller without redness or warmth, set your next check for week 2. If a spot grows or hurts when pressed, the next step is to have a doctor feel it and decide on treatment.

If you can’t tell which it is, Beautystone is a clinic in Seoul’s Hapjeong area, and you can start by sending one day-7 photo through the consultation button on this page.

Sources

• Re2O in one cheek compared with a hyaluronic acid skin booster in 20 people: International Journal of Molecular Sciences, 2026

• A pig-derived dermal matrix filler compared with collagen filler for smile lines: Aesthetic Plastic Surgery, 2026

• Common filler reactions, late lumps and blood-vessel warning signs: US FDA

• How long swelling and bruising last after fillers, and aftercare: American Academy of Dermatology