I Have Had A Skin Infection On My Right Hand

i have had a skin infection on my right hand for over two years now. it started just on my thumb and when i saw my doctor about it he gave me hydrocortisone cream. that spread the infection to my entire index finger, the tips of all the rest of my fingers, and the right side of my palm. since then, i went to a dermatologist and he diagnosed me as having a fungal infection. he's given lamisil tablets and Clotrimazole and Betamethasone Dipropionate Cream. That seems to work for about the first week or so then everything flares back up again and gets worse. I've tried 3 separate cycles of different strengths of the cream and tablets. Any advice?