My daughter is a cheerleader she was dropped on her head from a stunt in the air. How long should she wait to go to sleep.

If she lost. consciousness, or is experiencing severe neck pain or headache, or has altered mental status, take her to the ER instead of putting her to bed.
Sleep. If your daughter shows no neurological signs she can go bed at any time. Make sure you can rouse her from time to time during the night.