I hope you have been putting your hand in ice all day! That is the only thing next to prayer that is going to help it. In fact I'm pretty sure that God would answer that prayer by sending someone to tell you that you need to put that puppy on ice! The sooner the better because the cold is the only thing that is going to reduce the swelling now!!
If you go to A&E they will tell you to do the same thing? I suggest fill up a bucket with cold water and ice and sit next to it occasionally dipping your hand into it until it starts to hurt (too cold). Continuing this is the only way to reduce the swelling!
Also I would advise taking a couple aspirin. Not for pain relief if there is any pain but because aspirin thins your blood and is an analgesic and anti-inflammatory drug.
Trained First Aider.
What did you do by the way?
Prayers..