What Causes Recurrence Of Ulcers In Vagina Inspite Of Using Acidic Acid?

I have been to the gynecologist with a yeast infection that turned viral that caused ulcers around my vulva, vagina, and inside the vagina the doctor prescribed me 500mg of Valtrex for the problem but it seems to get better but then flares back up again it itches and burns so bad and i have been back to the doctor recently and he said that i was 70% better than the first time he seen me he burned the remainder of that ulcers off with acidic acid and it was followed with gentain violet...... The ulcers continuously come back though.... Is there anything that you can tell me that i may be able to get over the counter or what i could do to help. I even wear cotton underwear and nothing seems to be helping......