What Does Throbbing And Discolored Knee While Having Patella Femoral Pain Syndrome Mean?

Okay i have a knee disorder called patella femoral pain syndrome.I recently fell on my knee now i have this know looking thing but when i walk or touch it which hurts it is like it has water in it.My knee stays swollen even if i keep ice on it.My knee is continually throbbing and is black and blue what could be going on and how can i fix it?