Would it be safer to do microdermabrasion or a chemical peel on skin after accutane?

Neither!: It depends on how long ago you stopped your accutane, but if it has been less than a year, i'd recommend avoiding any type of surgery or inflammation-causing procedure. The risk of scarring is low with both of these procedures (the least is microdermabrasion), but whatever those risks are, they are multiplied significantly with accutane-stimulated skin. Just say no, be patient or worse can occur.

Neither is safe: Dermabrasion, chemical peels and lasers all work by damaging the skin in a controlled fashion to promote deposition of new collagen. Accutane can cause significant scarring with any of these types of skin resurfacing procedures. To be safe, one year off of your Accutane is recommended before performing any of these.