I wanted to see if anyone else has dealt with this. I have this large ball on my knee cap that's filled with fluid. It's dark red and looks like there is a golf ball under my skin. It hurts like hell and i can't kneel on it which makes it close to impossible to go to BJJ class. I don't want to miss anymore time. Does anyone know if i can have it drained or any other way to help it heal? I will call the doc soon if it doesn't go down.