Ouchy. I get these sometimes. I just moisturize, moisturize, moisturize. Especially after getting into bed so it can soak in over night. Then tape it together during the day with medical tape or a big band-aid. After it is somewhat sealed, I usually use a scraper (like a Ped-Egg) to file the callous down a little so it doesn't stay as rough. Then more moisturizer... until it's all healed and I forget I ever had the problem and stop using moisturizer on my feet so they get dried and cracked again and my heel splits. Repeat cycle.