A foot file is one way that you can self care for cracked and thick skin around the heels:
Cracked heels do not get better by themselves. That cracked hard skin is dead skin and can not heal back together. That cracked thick skin needs to be removed so any cracks in the good skin beneath it can be given the chance to heal. There are several causes for this. One way to help reduce this is to use a foot file simply by rubbing over the area to file down the thick hard skin. You have to be careful not to go to far and often going “too fast” it can get a bit hot, so go carefully and slowly. This is similar to using a pumice stone, but they are often not rough enough to get much off, so you need a good foot file. Once the hard skin has been filed down, then use a good foot cream to hydrate the skin.
Better yet, go and see a podiatrist and get them to expertly debride that thick and harder skin. After that you can use the foot file and a good cream to keep the problem under control over the long term.