I have had some sort of virus the last week. I have eaten nearly nothing the last 6 days. I have had sweats and stiffness, and any small amount that I did eat has gone straight through me. I have had no appetite all this time. I now also have 4 very painful spots on the gums in the four corners of my mouth, which cannot be touched by food, fluid, hot or cold, or air, without excruciating pain. What could this be?