I had black rough and thickened skin on my penis head, a dermatologist had diagnosed it at frictional dermatitis and prescribed me tacroz and cetaphil moisturizer but when my condition didn't improve after 2 months of medication he prescribed my momate s ointment for a week but after using it for 3-4 days my skin became more extremely rough and blackened, now what should I do restore my skin back ,please help me.