My 14 month old bangs her head at night, is this normal?!?

When she was born she would take a pacifier, then she got thrush and wouldn't take it anymore, she started sucking her thumb but a couple months ago she got hand foot and mouth disease so she stopped doing that. Now when she goes to bed no matter how tired she is she bangs her head against the side of the crib. The padding is still on but it sounds terrible!! Will she stop this or do I have to do something?! I'm afraid she will do some damage!!