In short. CO2 laser resurfacing carries a short list of risks that should change a decision: infection in the first week, delayed healing and scarring, and permanent lightening of pigment. Redness, swelling, oozing, crusting and itching are the expected course of healing rather than complications. Scarring is uncommon but real, and pigment loss has no good correction.

Key points

  • Redness, swelling, oozing, crusting and itching are expected, not complications.
  • Infection risk is highest in the first week and is treated promptly.
  • Scarring is uncommon but more likely after infection, deep treatment or keloid tendency.
  • Lightening of pigment is uncommon, can be permanent and has no good correction.
  • A written plan should name out-of-hours cover before treatment starts.

Which effects are expected rather than complications

Redness, swelling, oozing, crusting and itching are part of the treatment rather than complications of it. So is a period of increased sensitivity, and so is the pinkness that persists for weeks after the surface closes. Patients who were warned about these cope with them; patients who were not often think something has gone wrong when nothing has.

When does infection become urgent?

Open skin can become infected, and the risk is highest in the first week. Antiviral cover is ordinarily prescribed, because a cold sore erupting across healing skin can leave scarring, and bacterial infection is treated promptly with antibiotics. The signs to act on are increasing pain after the third day, spreading redness, heat, discharge, or a fever. Treated early, infection usually settles without lasting harm. Ignored, it can scar.

How delayed healing turns into scarring

Some areas heal more slowly than others, and healing that lags raises the risk of a scar. Scarring after resurfacing is uncommon but real, and it is more likely after infection, after treatment that was too deep for the skin, and in people with a keloid tendency. It is also more likely on the neck and on thin skin. A scar that forms is treatable, but it is easier to avoid than to correct.

What the clinic should set out before treatment

A written plan should say what will be treated, how deep, what the healing week involves, what to do if something goes wrong, and who to contact out of hours. Inside a hospital, that contact is backed by dermatology and surgical cover rather than a mobile number. Ask what happens if you develop a problem on a Sunday night.

Why lightening is the complication without a correction

Darkening after treatment is common and usually temporary. Lightening is uncommon and can be permanent, because pigment cells that are lost do not reliably return. It is the complication with no good correction, and the reason resurfacing depth is chosen conservatively in darker skin and on thin areas. It is also the reason an aggressive plan deserves to be questioned rather than admired.

Complication Signs Timing What the page says
Expected healing effects Redness, swelling, oozing, crusting, itching, sensitivity During and after treatment Part of the treatment rather than a complication
Infection Increasing pain after day three, spreading redness, heat, discharge, fever Highest in the first week Treated early it usually settles; ignored it can scar
Cold sore outbreak Sores across healing skin While the skin is healing Antiviral cover is ordinarily prescribed
Scarring Healing that lags behind the rest When healing lags More likely after infection, deep treatment, keloid tendency, neck and thin skin
Darkening Deepening colour after treatment After treatment Common and usually temporary
Lightening Skin paler than its surroundings After treatment Uncommon, can be permanent, no good correction
Blistering or dusky patches Blistering, grey patches, a sore not crusting like the rest Any time after treatment Needs review the same day

When should you seek review the same day?

Seek review the same day if pain is worsening after the third day, or if one area is hotter and more swollen than the rest. The same applies with a fever, spreading redness, or discharge from the treated skin. It also applies to blistering, dusky or grey patches, or a sore that is not crusting like the rest.

What the consent conversation should contain

None of this makes resurfacing a bad treatment. It makes it a treatment with a real consent conversation attached, and that conversation is worth more than the form you sign at the end of it.

Sources

Source links open each organisation's search results for the topic. Document-level confirmation is pending the reviewer's sign-off.

Internal links

Frequently asked questions

How likely is scarring after CO2 resurfacing?

Uncommon, but real, and the risk is not spread evenly. It rises after infection, after treatment that was too deep for the skin being treated, in people with a keloid tendency, and on the neck and other thin-skinned areas. A scar that does form can be treated, but avoiding one is far easier than correcting one afterwards.

What are the signs of infection after resurfacing?

Pain that increases after the third day instead of easing, redness or heat spreading beyond where it was, discharge that smells, and fever. Cold sores erupting across healing skin are a particular concern, which is why antiviral cover is ordinarily prescribed. Infection treated early usually settles without lasting harm; ignored, it can scar.

Can a complication be corrected afterwards?

Some can and some cannot. Infection caught early usually resolves. A scar can be treated but not erased. Pigment that has darkened usually settles with time, protection and prescribed creams. Pigment that has been lost is the one with no good correction, which is why depth is chosen conservatively in the first place.

Risks & Limitations

  • The treated surface is usually open for five to seven days, weeping and crusting, with redness that persists for weeks afterwards.
  • Post-inflammatory hyperpigmentation is the commonest unwanted effect; it is more frequent and more stubborn in darker skin and can take months to settle.
  • Pigment loss (hypopigmentation) is uncommon but can be permanent, and there is no reliable way to restore pigment that has been lost.
  • Infection of open skin, which is why antiviral cover is ordinarily prescribed; increasing pain after the third day, spreading redness or fever needs same-day review.
  • Scarring, uncommon but real, and more likely after infection, after treatment that was too deep for the skin, on the neck, and in people with a keloid tendency.
  • The improvement is long-lasting but not permanent, and sun exposure after treatment fades it faster than anything else.

When to Seek Care

  • Increasing pain after the third day, or one area much hotter and more swollen than the rest of the treated skin.
  • Fever, spreading redness, or discharge from the treated area.
  • Blistering, dusky or grey patches, or a sore that is not crusting like the rest of the face.
  • A cold sore erupting across healing skin, which should be reported the same day.
  • Swelling that makes it difficult to see, or any new change in vision, which needs urgent review.

References & Further Reading

  • American Society for Laser Medicine and Surgery (ASLMS) — patient information on laser and energy-based treatment
  • American Academy of Dermatology (AAD) — guidance on laser resurfacing and post-inflammatory hyperpigmentation
  • National Institute for Health and Care Excellence (NICE, UK) — relevant guidance on skin treatments
  • Cochrane Library — systematic reviews in skin resurfacing and scar management

Medically reviewed by Ke He, MD (何锞), Deputy Director & Head of Skin & Laser Aesthetics. Last reviewed: 19 September 2026.

This page is patient education, not medical advice, and it does not cite individual studies. Discuss your own case with a qualified clinician. To arrange an assessment at Chongqing West District Hospital, see Contact & Consultation.