Does acanthosis nigricans fade away if you lose weight?

Possibly: If you truly have acanthosis nigricans, it's often very difficult to treat. Make sure it doesn't just wipe off with an alcohol wipe, though! if it does, you may not actually have an--see your dermatologist. Most important, the underlying cause (such as obesity) needs to be identified and treated, as this can sometimes "cure" the skin. Otherwise, some lasers and prescription creams can help.