Pinpointing Knee injury???

[trix]

about 4 months ago I blew out my knee, walking down stairs, It was dark, was waiting on what I thought was the bottom landing while someone turned the light on. ai took a step forward,not realizing there was one more step, My knee went to the right,(too far, then to the left,too far) I saw white and had a hard time walkin...Since I have worn a brace, Gotten xrays, Now there is a lump on the back inside of my knee, I can't figure out if it's maybe a torn ligiment or tendon. It's not as painful as it was and I have my good and bad days. I was wondering if it sounds like something that can be rubbed out. I know I need an MRI, it's difficult with no insurance...any input...No sarcastic remarks please...I know it's obviously a problem, just seeing if anyones ever been in the same spot?
The brace I'm using is Rubber(spandex) Reinforced with Stainless steel for each side of the knee,it helps when I over due it...