Sounds like you're developing a hot pocket. When you were landing, was your ankle folding with your toes sort of going up to your shin?
You could do some light physical therapy on your own, but your ankle will still probably be pretty weak by next weekend.
Maybe try the R.I.C.E. method (rest, ice, compression, elevation). Trace the alphabet with your toes to stretch your ankles. Use a wobble/balance board and those big rubber bandings for resistance. Maybe bicycle and swim. Get some painkillers for the contest.