A few weeks ago i was mucking about and smacked my hand off a wall. Hurt abit and started swell but didnt think anything off it and carred on mucking aroun. Went to the docs the next day cos my gf was nagging me to. Turned out i had a really bad fracture in my hand. Might of needed an op on it to warp wire around it. So you might want to get checked just incase.