Mumsnet hasn't checked the qualifications of anyone posting here. If you have medical concerns, please seek medical attention; if you think your problem could be acute, do so immediately. Even qualified doctors can't diagnose over the internet, so do bear that in mind when seeking or giving advice.
Help! Any horned hoofy type people out there today?
I'd be inclined to rub a generous dollop on Lansinoh on, cover it with a plaster or micropore, and wear socks until it heals, even if it turns hot again. If you get the chance, soak your feet every evening in warm water with honey and lavender oil mixed in, before applying some more Lansinoh. Keep the crack clean and covered with with Lansinoh, and, IME, it will seal within a few days and you can go back to regular moisturising. But avoid filing or scrubbing until it's completely healed and pain-free. BTW, the outer layers of skin will not seal, but you will know when it's healed as much as it can.
Sorry I opened this thinking you were calling all Capricorns. But obviously not.
Although, I have had a cracked heel before. Think, as others say, the secret is keep moisturising. I used Sudocrem on mine (on the advice of a chiropodist) and it did help, although the remains of the crack are still visible. I treat it by regular gentle use of a pumice stone and lots of moisurising. A chiropodist will be able to scrape off excessive hard skin which will give you a bit of a head start.