I would love to help you but i'm a little confused.. what letter did you post?
why exactly is your knee killing you? If there is swelling, I would suggest taking the pressure off of it by elevating it a bit and icing it like AI says.. Have you consulted your doctor about your knee pain yet? If not your physician, how about your trainer? I notice you mentioned that you're an athlete.. maybe the trainer has some suggestions/ideas about what's going on with your knee?