DDs little toenail seems to be coming off

[TheDevilWearsPrimark]

I've only just noticed. It's a sort of creamy yellow colour and seems to be coming away from the cuticle at the bottom. She says it doesn't hurt.

Any ideas why or what to do, should I put a plaster over it?

I would just leave it, if it was me.
If it does fall off, a new one will grow, eventually
probably best to let it stay uncovered, so it doesn't get damp and grow nasties