How to fix my ankle fast?

I hurt my ankle skateboarding last week, it cracked but didnt break. Its fine now although the back of my ankle still hurts when i jump, how do i fix it quick, im currently usimg a foot cast

Sounds like an ankle sprain. Take some ibuprofen for the pain and to help reduce swelling as per the directions on the bottle. Ice your ankle down for about 20 minutes and keep it elevated to reduce the pain and swelling. Before practice wrap it in an ace bandage for support. If the pain and swelling do not diminish then you need to see a doctor. Inform the coach before the tryout that you injured yourself. If the school has a trainer, go early and have them take a look at it. If you let the coach know your injured and give a 100% effort at the tryout then that will go in your favor. If the pain is too great, see a doctor and don't risk further injury which may keep you out longer.