What are the adverse effects of dermabrasion?

Permanent scarring. Dermabrasion can lead to permanent scarring of the skin if it does not heal well, gets infected or is taken too deep into the skin. The skin can also change color and become darker.
Minimal if skilled. The risks are minimal in the hands if a skilled practitioner with postoperative compliance with the recommended skin care program but infection, ulceration, scarring, hypo/hyperpigmentation, keloids, atrophic scars, contour irregularity, as well as persistence of existing scars are some possible complications.
Pigmentation. You may have either darker or lighter pigmentation following dermabrasion. Scarring is also a possiblity. You might want to consider a series of microdermabrasion, while will not give the same "immediate" results as dermabrasion, are cumulative in effect.