Well, if all you do have is an MCL injury then your pretty lucky insurance wise. These injuries heal on their own but you have to treat it correctley. If your knee is still swollen, I suggest you start putting ice on it, and rest yourself for a couple of weeks (meaning don't go out and play sports...or go snowboarding!). Once the swelling goes down and your leg starts feeling more stable, start swimming (it's a big help!) You can also start doing leg strengthening excersizes on weight machines, and focus a lot on the quads and hamstrings. These muscles help support your knee. Whatever you do, don't underestimate your injury, even if you start to feel better don't get cocky on your feet, it take 6-8 weeks for an MCL to heal, maybe even longer. You should also make sure that you have not damaged anything else in your knee like your ACL or cartlidge. MCL injuries are sometimes coupled with other injuries to your ACL, meniscus etc. Good luck!