My gum is a little swollen more info?

Last night I went to Sakura and I was eating some filet minion or however you spell it and after I was eating I noticed my right side of my mouth hurt so felt it with my tongue and it was kinda big. Not really big but at least big enough that it hurts when I chomp my teeth together. This never happened before when I ate Sakura so what do you think is wrong?