I injured my left knee in a ski fall in April. I badly ruptured my medial ligament and snapped my anterior cruciate....doh! As long as you haven't snapped it completely then the medial ligament will get better on its own, but may be painful for 6 months. Lots of ice and keep it moving.
If your fall had a twisting component, and especially if your weight was backwards, then you may need to get the ACL looked at. Did you hear a popping sound as you fell? A good physio should be able to tell by doing a Lachman test. hopefully it's in one piece as unfortunately surgery is the only solution if you want to do sports like footie or skiing! I'm now 6 weeks post-op!