Put him in a salt bath 2x a day.
Put a thick layer of vaseline on the nappy for every nappy change x

Put him in a warm bath I can't remember now if it was once or twice a day it really does help, what did the doctor ask you to do? Mine asked me to put plenty of sudocream on a tissue and then put the nappy on, I gave my son calpol every 6 hours i think to make sure he wasn't in pain also advised by my doctor.