Originally Posted by
miokomioko
It's an infection in the gums and it's really common. It happens because of how the gums are usually still folded over portions of the wisdom tooth, creating a generous pocket for shit/food to get stuck in and become infected. I recommend taking the ibuprofin of your choice, brushing the hell out of it, and swigging plenty of mouthwash in that zone. It will ache for a while, but it it should generally go away by the next day. I have had this happen 2-3 times when my wisdom teeth were peeking out.
tl;dr: brush moar