What Is The Remedy For The Pain In The Leg With Stiffness And Swelling?

I fell today from walking on uneven grass with high heels. I was fine for about 2 hours after the incident. My door hurt a little but I could even walk in my heels without much pain. After sitting still for two more hours, my foot began to throb and I was barely able to walk because of the pain stiffness and swelling. The pain is mostly in my instep area. I went to the hospital but they said nothing was broken and to take naproxen sodium,and to ice and elevate it. I have a fever of about 100*f and am still in a lot of throbbing pain even lying still. Could it be fractured/ broken and they films just didn t show it? What can I do to alleviate the pain?