What the hell? This afternoon I discovered a blood blister in the back of my mouth. I have no idea how it got there. It's not painful, but very annoying (like there's is something stuck in my teeth and I have to touch it with my tongue all the time). I asked for advise from the web, friends and family and they all agree I should not pop it, however tempting that is. I just have to wait until it goes away. Yuck.