Why are my feet sooo dry?!?

okay i have really really dry feet and its gross to me and annoying. no matter what i do nothing works. its not only my heels that are really dry its my whole entire foot. all in my toes too. i was them and put lotion on them but still its alwasy dry and nasty. either the skins flaky and comes off or i pull it off. i need some help what do you think is up? i've also been dancing for 13 years could this hae anything to do with it? but even when im on my off season of dance it still happens