hello, i was bitten by a flea about a year and a half ago, the bite was on my crotch which caused a rash that wont go away. ive been to the dr and he prescribed different ointments such as ketoconazole, cortizone and even anti biotics and when i use the ointments it gets worse. foot powder helps a little because it keeps it dry but it doesnt go completely away. what do i need to do ?