There are some possible side effects of using laser treatment, including:
Aggravating cold sores. If you have a history of cold sores, laser treatments can aggravate them, especially if the treatment is around your mouth. Let your doctor know if this is a concern, and they should be able to give you an antiviral medication before the treatment.
Milia. Milia are small, white bumps, similar to tiny whiteheads. They're not a serious complication but can be annoying or unsightly. Gentle exfoliation with a warm cloth should remove them. If this doesn't help, your dermatologist can also remove them.
Hyperpigmentation. There may be a darkening effect on your skin after laser treatment. You can use a skin-lightening cream if you're concerned about it. You should also use sunscreen with a minimum Use an SPF 30 if you're spending time out in the sun after treatment.