Funny that Carole above said "till the cows come home" in her thread. Because my sister had (and may still have) this problem, partly because she usually refuses to wear shoes.
She found the only solution was to use bag balm, what they use on cows utters. She would apply the balm and then put on socks at bed time.
Here is what the can looks like. I believe you can find it in a pharmacy.