Compared to certain other plants, peace lilies don't need to be pruned very frequently. However, if, for whatever reason, one or more of your lily's limbs or leaves become brown or wilted, you may want to prune the leaves to keep the plant from wasting energy on the dying appendage.
Accutane is a retinoid, and not related to anti-biotics so the side effects are different. However, the list of potential rare side effects of accutane is long and includes headaches, nausea, muscle pain and depression.
Accutane is helpful in Cystic Acne and Hidradenitis Suppurativa. From the images you provided, you may be suffering from Hidradenitis Suppurativa. This condition has lesions similar to cystic acne, but the cysts are more severe, often are joined by pus-filled tracts, and are seen in areas typically not affected in acne vulgaris, such as the groin and axillae area.