Barb, fwiw, I also had (and, two months later, still have--though they are healing at last) those patches and was told they are all a part of mucositis, not thrush. Because my lower teeth are not saliva-coated anymore, my lower lip rubbed against them during rad and produced those pacthes.

In fact, I have white patches in a couple of places on the lining of my cheeks too--same deal. Don't be surprised if they take a while to heal.