I'm sorry your little one is suffering like this. My advice would be to get all chemicals off her skin as often that is the cause. Can you try her in cloth nappies and see how she responds? Although they don't draw urine away from the skin in the same way, it is often the chemicals that cause disposables to be so absorbent that irritate sensitive skin. Also if you are using baby wipes then stop and change her nappy with warm water and cotton wool (organic if you can get it). Takes a bit of getting used to but it cleans bums up very well and in my boy with eczema it sorted out his nappy rash within 48 hours. Good luck!