Well a few months ago I got hit in my knee with a glass picture froame and it had a pretty big gash in it but I didn't think that is was bad enough to go to the hospital so I treated it at home.It took a little while to heal and now there is a scar that is red and in one part it look bluish purple.The scar doesn't hurt but I get random pains in my knee.What could this be?

Did you get all the glass out of your knee? There could be a teensey piece of glass still in there causing all sorts of problems.