penis or nummular dermatitis. I would suggest you to get a KOH examination of the skin scrapings done along with biopsy skin to confirm the diagnosis. Nummular dermatitis is a type of eczema and steroids used for this may worsen the condition if it is a fungal infection.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your dermatologist. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.