Hi There, I Have A Patch About 6 In Long

Hi there, I have a patch about 6 in long and 3 inches tall of lichen sclerosis on my back. Recently, I was prescribed lamisil for treatment of several ring worm spots on my body. I have been feeling nauseous all day, so was looking up side effects of the lamisil, and noticed it says it should not be taken by those with autoimmune disorders? Any advice on this??