Hello and welcome to JustAnswer,
how long has it been there?
did you bite your cheek?
is it painful?
does it bleed?
Then this is almost certainly a 'blood blister'.... that's what it looked like to me without knowing the history, but now that I know that you were out drinking last night and are not sure where this came from in such a short period of time this is almost certainly from trauma.... biting your cheek, and will go away within a few days.
I did review the literature regarding dangerous or concerning lesions of the mouth and buccal mucosa (that's where this is.... the buccal mucosa) and THE REFERENCE IS HERE. And while this looks like the hemangioma picture it is not because hemagniomas do not pop up overnight.
This is a simple blood blister and should go away in a few days, in fact, since it is sticking out you may bite it by mistake and it will bleed, but if this happens, it will still go away no problems.
I am standing by if you have any questions.