I hurt my finger today. Hit it accidentally against a stair banister. The finger cracked. Now one index finger is twice the size of the other. The skin also looks...tender/taut (lol). Also my finger is stuck in a sort of bent position and won't flex straight out.

Should I seek medical attention or leave it, get some cream or what? Could I have dislocated it? Its stuck in a really funny position and if I try to force it to straighten it hurts/won't go.