is it sprained, black and blue and you can't bend it?
I would say like a week, but if it's not that bad it could be just a couple or few days.
Ice it!! all around your finger. Also, after icing it it's good to put it in warm salt water to help the swelling. and kind of lightly massage it while icing or putting it in warm salt water.
Were you doing it on floor and your finger went under, or did you hit something, like your spotting coach?