My Keegan has had skin problems forever. Ivermectin did not work for her and I got SICK of vets. I did some homeopathic research and found happyjackinc.com >> they have a product called Dermicide Ointment. It comes in a 4oz jar and smells horrible. But my Keegan's hair has all grown back (even in the places the vet told me she wouldn't be getting any hair regrowth).

Maybe try that too?