S.B.
If there is no swelling or bruising and it's just sore, she probably just twisted it and she'll be fine. If she had sprained it there would be definite swelling. Treatment for a sprain is RICE, rest, ice, compression, elevation. Ibuprofen helps for the pain. Even if it's just twisted, I would suggest that she stay off of it for a few days as much as possible and be extra careful to not injure it further. I've twisted and/or sprained my ankles more than I'd like to admit, so this is all coming from experience. Of course, if it's not getting better, or if it gets much worse, you may want to get it x-rayed to be certain there is no fracture. But it really sounds like it's just twisted, and not serious or cause for alarm. Hope she feels better soon!