My left knee feels like it is swollen...?

It would be smart not to risk it like I did and caused myself surgery. Get an x-ray first and if nothing shows up get an MRI. If your knee twisted on impact it could be a ligament tear which could need surgery or physical therapy. Just get it checked out to make sure nothing is wrong. The swelling is from something right? Hopefully its just a bone contusion or something not serious. Good luck.