In cold weather my thumb and index finger pads develop horrible,
painful cracks at the corners where they meet the nails.
My fingers do the same thing. Where the cracks develop, there is
usually a thick layer of dry skin. The dry skin actually prevents
the crack from healing because, as the skin dries, it shrinks,
pulling the crack open even further, and making healing next to
impossible. I take a fine emery disc on my flex shaft and put it
to the crack. Drives my family crazy, but it doesn’t hurt because
of the callous skin, and removing most of the dry layer allows the
more plastic skin layers underneath the re-adhere and heal. Works
every time, and very quickly. Probably removing the thick skin
layers periodically would stop the cracks from occurring in the
first place, but I’m not together enough to have tried that yet!