My SIL used Denestin (available at shoppers) and it worked wonders on my nephew. Everything else was working but not very well. He had a bad rash for over 2 weeks and with using the denestin it took 2 days for it to be all gone!

Also one of my fellow dcp swears by Burnt Flour. You litterally in a clean frying pan stir around some flour until it gets a brown colour and use a salt shaker. apply at every diaper change.