It may depend on how soon the recital will take place. Most soft tissue injuries take six to eight weeks to fully heal. Dancing on it too soon (before full recovery) can result in reinjury or another ankle sprain.
And most dancers spend hours practicing in the final days before the performance. So, that pushes the time frame up sooner for returning to full activity.
Studies show that although the athlete (dancer) with a healed ankle sprian demonstrates what looks like normal motion and strength (when compared to the uninjured ankle), specific testing shows this isn’t always the case.
Even mild or occasional pain and/or mild, residual swelling can cause a dancer to favor that side. The best way to work through this may be with a physical therapist. The therapist can show her how to train to restore normal motion, strength, and flexibility needed for dance.
Attention will be paid to ankle proprioception (joint sense of position) and kinesthetic awareness (joint sensitivity moving through space). Both of these finely tuned functions are needed for complete restoration of normal movement and function.