ulcerated mouth sore thing?
 

i was at the dentist today to have some sealances redone and to have a bond thing stuck on a tooth where enamel is eroded and wearing away or something, and my dentist was like "hey did you bite your left cheek? you have a sore there that's ulcerated?" i had absolutely NO IDEA what she was talking about, haven't bitten anything that i know of and my cheek isn't swollen or anything. i was confused so she got a mirror and showed me. inside my left cheek is this round spot smaller than a penny (sorry UK people i don't know your coinage) that is all blackis/bluish/redish (yea it's disgusting and weird i'm sorry). it doesn't really hurt though, i mean i didn't even know it was there! i didn't really ask questions i was surprised and confused and wanted to leave because at the dentist i am always afraid she is going to notice signs of purging and that it will be awk, you know? it's really hard for me to talk about. she just said to be sure not to bite the area again (she seemed to think i had bitten it or something) so that it could heal. anyway, ideas? is that what probably caused this or could purging have caused it? i tried to wiki and google ulcerated mouth sores and i didn't get too far, most of the results were squamous cell cancer and canker sores and i have never had one of those and the pictures look different.

Is it raised at all?
I've had by your description the same thing, I get the often- resulting from purging. They do go down by themselves, but it's a sign of the effect of purging on your health. Take care sweety.
xxx

Potentially purging could cause an area that is irritated/ slightly burnt and then food wearing against it/ further purging/ accidental (or purposeful!) biting of your cheek can lead to it ulcerating. Then further purging or whatever could prevent it healing as well.