Yes- try a few very light Glycolic peels. I usually start my patients with %20, then $25%, %30 and maybe even %50 glycolic peels. Please do it in a doctors office. In addition you should use SPF 30 and a bleaching cream (2% Hydroquinone). These treatments are safe even while on Accutane.
I would not recommend doing a chemical peel on your abdomen, treating an area that large is not ideal with certain types of peel, also the result you will get from the peel is not going to satisfy you. It sounds like you have skin laxity and unfortunately this can not me treated with a peel; too...
Chemical Peels is an excellent treatment designed to over-turn skin cells to improve texture, and tone.
Chemical Peel Benefits Include:
Reduces fine lines, and wrinkles
Exfoliate sun damage
Treat pigmentation (such as Melasma)
Acne
Mild Scarring
Always discuss possible side-effect...