Ask her why.
Find out why.
Find out what causes these compulsions.
It may be the start of OCD, it may be something entirely different.
But you need to communicate more.
She may be 5, but she still needs to feel heard, understood and cared about, so you need to ask her why, sit down with her and explore this issue.

If it does persist, maybe it is time to go to a doctor & explain this.

Good luck.