Ouch! Cracked skin is no fun. I don't know if this will be any good for you, but its worth a try
whenever I get dry, cracking skin inbetween my fingers I use Neutrogena Norwegian Formula concentrated hand cream (the unscented one) it works a charm. It comes out as a sort of ointment, and a little goes a loooong way.
I happened apon it years ago. I had really really bad contact dermatitis on my hands and up my arms (worked in a cafe and the constant hand washing and dishwasher chemicals did me no good). Tried loads of otc products eg atrixo (trust me on this one, do not buy anything like atrixo that is scented, hurts like a biatch! and in my case made things a lot worse). Finally I went to the drs and alongside a steroid ointment (eumovate) the Dr advised me to use the neutrogena. Out of all the hand creams I have ever used this is the best, and it lasts for a long time considering the size of the tube. It's not too pricey either, I think around £3 - £4.
Also the suggestion aboot putting on cream and then wearing gloves to bed is really worth a try.
xx