My 2 yr olds toenail just came off?? what THE?

idk if she slammed it or what? i noticed it was lifting from her skin so i started putting peroxide on it every now and then. after her baths i put a band-aid around it so its been fine. she hasn't been complaining, no blood or anything and she actually pulled it off herself! i was watching her from the kitchen and i almost yanked my hair out by the roots!! geez!...she gave me her whole little toenail and her toe just looks so plump and weird it kinda looks like one is growing already but it doesn't look right i guess ill just have to wait and see i put neosporin and another band-aid shes fine but i jus wanna know why does this happen sometimes? this is the second time its happened to her. same thing probably about a yr ago. does she need iron or potassium just curious.. this seems pretty common to me? happen to anybody's little one? any advice is good! thanxxxxx bunches byee ;)