How To Treat Sprained Ankles After A Fall?

Hi, I fell down the stairs about two weeks ago and sprained both my ankles, my right ankle is about 90% healed, but my left ankle isn't. I have a knot thats about 1 inch all around above my left ankle. It hurst only when i've been sitting for a while, but once i'm up and moving around - it doesn't hurt that bad. Could it be a skin infection from the fall?