swollen knee for months?

I'm 16 and I play soccer, during a game I had a direct blow to my right knee. it instantly swell and bruised on the inner of my right knee. I iced it and kept it elevated for a week but nothing changed. sometimes if I've been sitting where my knee is bent and I try to stand up it buckles. it's know been 4 months and nothing has changed except the bruising has gone away. it's still numb in the area and down my leg a bit also it's swollen. i only have pain when the area is touched but otherwise walking is fine.