Hi Jayneday: What does it look like? I have what looks like a pimple (red with white in middle) come up on my front gum right above a tooth that had just had work done on it, under a bridge. It has an old root canal. The oral surgeons (two) said the pimple (sometimes white middle goes away) is almost always indicative of an abscess. After X-raying mine, it showed infection up in the gum and I am set to have what they call an apicoectomy in a week or so, which is where they cut the gum above the tooth, cut the tip off the root, remove infection and sew gum back up (eek). Oral surgeon, of course, says it isn't any big deal, (for him, it isn't!). Anyway, you might have something wrong with one of your teeth near the ulcer, and it could be an abscess or infection. An oral surgeon should be able to check this for you. Let us know what you find out, and I'm exactly like you as far as "freaking" when something new shows up in my mouth, so I certainly understand your concern.
julieann