Hi, about a week ago, i found a small normal looking pimple on my left knee cap, so i poped it and cleaned it out, well everyday it started growing and now my left knee is all pink, very tender, and very swollen, also everyday lots of puss and blood comes out, and now the muscles around my knee are hurting very badly, and my knee starts to feel like it is locking up, its very hard to walk or stand or bend it, but if I do not move it every so many mins, it feels like it is imposible to move it at all then, and gets more painfull, do you have any ideas on what this could be? Thans