I have an inflammed red sore with 2 white oval patches (looks and feels like an ulcer) behind top right molar.

I have an inflammed red sore with 2 white oval patches (looks and feels like an ulcer) behind top right molar. It is right where the palat meets the jaw. I went to a doctor yesterday because I was having slight difficulty swallowing and a sore throat. My doctor believes it to be allergies and gives me an antibiotic because she believes I may have an infection. I have been gargling with salt water, orajel mouth wash which is supposed to help mouth sores, and taking the antibiotics. So far, it has gotten a little worse and that worries me. It is not painful except if I press on it with my tongue. How long should I give it before I go to the next step? I am very aggressive when it comes to my health and, while I hope it is nothing more than a simple infection, I can't help wondering if its more serious.