I think the only thing I would try is using live acidophilus gelatin capsule pills as suppositories for a week. Use panty liners as there will be discharge as things equalize. Use Blistex on the labia to take out irritation and discomfort. If they haven't found any proof of bacteria then you don't want to use any Antibiotics , that could end up making any imbalances worse. Acidophlius will take care of a yeast imbalance, which is the most likely cause and one they never test for.