Scary bump in mouth. Should I be worried??

Okay, so I have a bump that just appeared while I was eating tacos from jackinbox. I dunno if it was related to the food. Looks like a blood blister and is semi firm and has no pain. Is unlike any other mouth bump I've had.

http://dl.dropbox.com/u/7960927/mouthbump.JPG



Sorry I have really bad anxiety and I get scared easy. Should I worry?? Thanks.