I was in a car accident 6 months ago and my knees hit the dash board, I've been in physical therapy with no improvement the suggestion is that I get a MRI it's moderate pain and does not stop me from daily activities and has little swelling, today however I noticed now I have a small dent on the inner part of my knee, still have light pain that's constant and my knee gets irritated if bent to long, minor swelling behind the knee. What do you think could be wrong ?