How does fractional laser resurfacing work?

The mistake this question invites is assuming that "fractional" means "mild." The word describes how the laser light is delivered, and it says nothing on its own about how safe it is for you.

How the light is delivered

my.clevelandclinic.org gives the core mechanism in one sentence: "Because fractional CO2 laser resurfacing delivers many narrow columns of laser light to your skin, much of your skin is not injured."

In plain terms, the laser sends many narrow columns of light into the skin, and the sentence says that much of the skin is not injured as a result.

Much is not all

Read the sentence slowly. It says much of your skin is not injured. It does not say none of it is.

That is why "fractional" is a description of the method and not a reassurance about the result. The method still needs someone trained to decide how it is used on your skin.

Settings and candidacy belong to a professional

Do not choose the settings, or the provider, by what the word suggests. The decision on whether you are a candidate, and how the laser should be set for you, belongs with a trained professional who has seen your skin.

If you want to keep reading before you decide, The Aesthetic Society page on laser skin resurfacing is one starting point. The American Academy of Dermatology guidance on how dermatologists treat sun-damaged skin and the my.clevelandclinic.org page on retinol, fillers and other wrinkle treatments place the laser among the other options.

When "fractional" is the whole explanation

If a provider describes the treatment only with the word "fractional" and cannot explain what the laser will do to your skin, ask again before you book.