Here is something you won't believe. I have the bad heal thing and just can't make myself wear shoes. Now I don't know how we would know if it from diabetes?

Anyway at almost any drug store type place or Walmarts etc., in the foot dept you buy what's called - I think shamy skin or something like that. It comes in square pieces about 4 X 6 or like that. It is skin colored. But it completely glues to your feet or wherever (not literally) but stays on well for a couple days.
Because that area gets no air, it softens up the skin and keeps it from cracking at the same time.

Also do the cream thing a few times a week and wear a light weight sock. they makes nylon ones that keep the air out. then in the shower each time you remove the shamy skin, use your cheese grater skin remover. You will be surprised if you really follow thru with this.

Of course just wearing good socks and shoes will solve the problem.