An easy home course of treatment to remember is "RICE"
R- Rest. If pain is persistent with activity, don't think that by getting back on it you can "work it out". Resting it may prevent further injury.
I- Ice. Apply an ice pack (with a cloth barrier between the skin and the ice) 20 minutes on 20 minutes off. This helps to keeo the swelling down.
C- Compression. An elastic wrap should be applied firmly, but not so tight where your foot is throbbing, immediatly after the injury and re-wrap it every 3-4 hours. This will help control swelling and pain
E- Elevation. Elevate the foot and ankle only to the level of your heart (usually one big pillow) is sufficient to help your body drain the fluid that accumulates at the injured site.
It is important to see a poditatrist as soon as you can to make sure you do not have a hairline fracture of the ankle bones and to get you on the right track towards recovery.