Any sore in your mouth that doesn't disappear in 2 weeks should be checked by your dentist.

I have the same thing. It doesn't hurt and I just noticed it today while eating a cookie. I can't remember if I bit my cheek recently or not, but I have bitten my cheek many times in my life and never gotten a bump like this as a result. I am so scared.

Have the same thing. This is the only info I found on the net an so far nobody's reported back it killed them so I'm not worrying :)

Perhaps dowen, that is exactly WHY they haven't reported back! Lol

Just kidding, you'll live but as I've said, if it's not gone in 2 weeks it wouldn't hurt to get it checked.

Its called Leukoplakia. Its something you get if you have HIV or if you smoke frequently. If you have it you should go to your dentist or some oral doctor and have them remove it.

Leukoplakia is a white or grayish patch that is irregular or flat texture and can have thickened or hardened areas. These patches cannot be wiped away.
Leukoplakia is NOT a red bump.

Don't worry everyone, its called Hematoma aka a type of BRUISE. Some vessels were damaged, probably from accidentally chomping on your cheek like I commonly do, and blood rushed to and filled the area. If you don't remember biting your cheek you could have done it in your sleep, or eaten something really crunchy where you didn't realize it. Just leave it and be careful not to bite it again while it heals up. :)

I've had this happen to me twice within 2-3 years. The blister is definitely filled with blood. The first time I got this perfectly round blister inside my mouth on my cheek, I was scared sh!tless and started messing with it. All of a sudden it popped and disappeared as the collected blood inside it leaked out. It's been over 2 years since then and tonight I discovered another one. I didn't pop this one though. I don't remember biting my cheek... but yesterday I did feel some soreness on the same cheek the blood blister is now located... so maybe I did bite my cheek while eating or maybe in my sleep? I am also a long term MJ smoker, but I doubt it has anything to do with this blister.

I'm not going to mess with this blister as I want to see how long it takes for it to disappear on it's own. Hopefully it won't be there in the morning.

Hey guys,
I noticed that I too had a black bump on the inside of my left cheek. I smoke, so I was worried. I also noticed that this black bump was level with my molar, so I thought it was a blood blister. I tried to pop it, and it did. A small trickle of blood came out, and no apin followed. I suggest looking on where the black bump is on the cheek. If its tooth level where mine was, chances are you bit your cheek, which I happene to do often :). Hope this helps.

I too have had several of these blood blisters appear in my mouth in the last few months.  If you look closely, there will also be a small red speck adjacent to the blood blister.  These particular blisters are not caused by trama (i.e. biting, chewing, etc).  It appears that the blood vessel below the blister breaks from some other mechanism.  Again, there is no biting in the middle of the night regarding this condition.  There's no pain or discomfort in the onset.  It virtually appears in a matter of seconds.  It can be on either cheek or the tongue.  I showed mine to my primary care physician today and he stated he'd never seen anything like this before.  My guess is that he's in his late 40's early 50's.  Because it is so unusual looking, he did not want to break it for a biopsy.  Instead, he's hoping it stays in tact long enough for a specialist to see it in a few days.  What differenciates this blood blister from a trama blood blister is the accompanying small red dot adjacent to the blister. If the doctor's come up with something, I'll sure post it.