Suggest Treatment For Rash On Scrotum

I have had a rash on my scrodum for four months now and have been to the doctor seven times. I have tried otc antifungal creams, prescription ketoconazole, Grifulvin for a month, diflucan for a month. I have good hygiene as i shower everyday and always wear clean clothes sometimes switching underwear twice a day. The only relief i had was towards the end of the diflucan treatment for about a week then it gradually came back. I have tried allergy pill and switched laundry detergent, shampoo, and body soap. I have tried otc eczema cream and every type and fabric of underwear known to man. What seems to offer the most relief is jock itch powder or baby powder. I have faith in my doctor that i have been to the last four times now but he is talking about doing biopsy and want to make sure that is the way to go before cutting on my family jewels. I have not been to dermatologist as I live in a smaller town and would have to be referred and drive quite a ways to get there and am kind of worried he will just try all of the same things. Any help would be greatly appreciated as I am kind of miserable at times especially while driving.