Talk to Dermatologist on Fixed Drug Eruption Patches

I have some past history of using acutane and isoterin for my severe acne along with Flagel(for stomach upset).My acne is gone but the medicine left me with 2 3 Oval shape Patches on my skin .One is on my nose and other two on my wrist. I have discontinue the medicine from these patches seems permanent . I have use multiple lighting creams recomended by dermatologist but no satisfactory results(Clarimax ,Synalar C,Sanclear).Further my Liver is functioning perfectly as per reports and usually i dont use any type of medicine.

Pictures of Pigmentation is attached .I would great if someone could determine the root cause and effective remedy