have you tried to use nipple cream? it has lanolin in it to help with tender cracked nipples on breast feeding mommies. i use it on my boobs and have started to use a little on my feet it helps. I have a really bad problem with cracked feet. it is on the ball and big toe. never had a problem until last year when i went to the pool. at night or when ever i take a shower i try and use a salt scrub on my feet then scrub with a loofa. this helps and if i use coconut oil to rub after the bath and then before bed put on a lotion that helps a ton. I would stay away from Vaseline because it clogs the pores in your feet so they will not "sweat". the udder cream will help a lot also. hope that this helps.