I jammed my middle finder at practice today. What can I do to make the swelling and pain go away?

R.I.C.E. Rest, immobilize (or at least don't carry anything- gentle range of motion okay if not painful), use ice 10 minutes on, 10 minutes off (repeat several cycles), elevate. If you start to lose sensation, if it is not improving, or if you can't move your finger, you should go to urgent care or er.
Ice and NSAID. Rest, ice and an anti-inflammatory medication - otc Ibuprofen or Naproxen (brand name: mortin and aleve). If pain and swelling is severe you may want to see your physician because you could have a significant joint injury.