First off, don't stress, it's okay. Sprained ankle isn't fun nor easy, but it won't be the end of the world.

Try to stay off of it as much as possible. Ice it whenever you can, all throughout the week, even when it's not hurting. Stretch and excercise it though with care every day. Like gently flexing it. Don't do any dancing that you absolutely don't have to do. Put as minimal amount of weight on it as possible. When you put shoes on, try wearing shoes that would offer the most support to your ankle, like sneakers, instead of something like flip flops.

If you're still sore on the day of recital, try taking some pain killers and still keeping as much weight off of it till the last minute. 

I hope you do well and are able to enjoy your recital to the fullest! Have fun!