What do you think could be wrong with my mouth?

A couple days ago I was brushing my teeth and noticed that while brushing it was a little sore on my cheeks, I looked and there was a small red sore like spot, not open or anything. Yesterday after dinner I noticed that I felt funny while eating and I checked and the insides of my cheeks, and inside my lips are all swollen and have splotchy red spots, it isn't super noticable swelling, but enough that I have that chipmunk feel and its kind of annoying because my front teeth keep catching on the inside of my lips. Any ideas? I haven't eaten or been exposed to anything new so I don't think allergic reaction is it, I have no idea. Thanks for your help.