Is it herpes or a canker sore?
Thumbs down for the first answerer! One white sore inside your mouth is mostly like a canker sore. This is not a cold sore, oral herpes, HSV1, whatever you want to call it. You may have bitten there, or you may have too much acid in your system. Try Oragel to ease the sensitivity. And yes, herpes is sexually transmitted although you can get HSV1 from kisses, towels, etc. as a child.
