I have a small hard bump on the roof of my mouth. It is about the size of a bb. It comes and goes. It will be there for about 3-4 days, then go away. Then a week or so latter will reappear. It is on the back of the hard part, of the roof, a little of center to the left. Always comes back, in the same spot. Only one. I also notice a sore throat. More like there is a dry spot, in my throat, on the left side. It doesn't hurt to swallow . Just feels dry. The dry spot in throat has been there for about 3 months. The bump on the roof of my mouth ismore recent. It has been going on for about a month. What could it be? I have heard everything, from hiv to herpes, to cancer. Very scared.