This sounds like irritation or eczema rather than yeast or fungus. I suggest stopping the ketoconazole, which kills yeast or fungus, and using a mild hydrocortisone, like 1% hydrocortisone, available without prescription. Wash gently, moisturize if ou want.
I think that will clear your up. If it doesn't do so in a week, show your doctor again.
Take care.
Dr. Rockoff