Hello. It's nearly impossible to identify a dermatological disorder without an examination, so you'll have to see your doctor about this issue. However, one possible diagnosis that comes to mind is
psoriasis, which sometimes involves only the head of the penis. Unlike in other areas of the body, where psoriasis is manifested by thickening and silvery-white scaling, psoriasis of the
glans penis can appear as a flat, pink to red patch. In some individuals, penile psoriasis causes itching, burning or pain, but in many men it's asymptomatic.
To a large extent, penile psoriasis is treated like psoriasis elsewhere on the body, but special precautions must be taken to avoid thinning or irritation of the fragile skin on the glans. A brief trial (no more than two weeks) of over-the-counter
hydrocortisone cream would be worthwhile to see if it invokes a response, but you should really see a
dermatologist to confirm your diagnosis and outline a long-range plan; psoriasis is a chronic condition.
I hope you have some answers soon!