If your knee is all still swelled up, dont go to the doctors right away, he'll just tell ya to come back when the swelling is gone so he can see what the damage is.  Put lots of ice on your knee and take it easy, Crutches can help is you have trouble walking. Or you can just wrap a bandage tightly around your knee, that always stabilizes it and diminishes the pain.
I over-rotated a D-spin in the Whistler backcoutry a few years back and when I finally made it down to the hospital, the doctor told me that I had torn my ACL and probably my PCL too and that I had to get surgery.  I was so depressed. I believed him cause well, as an emergency doctor at the Whistler village Hospital, he must see so much of this type of shit. So I got a apointment 3 weeks later with a surgeon and when I met him, the swelling was gone and, and he told me I only had light tear on my LCL which does not require surgery, just some time off!
So, in resume, take it easy, lots of ice and tight bandages for a few weeks till the swelling is gone and then go see a specialist. Take the appointment right ways actually. Good luck man....