Does the idea of something in her wee burning the area sound plausible? Both mine have had bad skin reactions on their bottoms when I eat certain foods and breastfeed. For ds it was thrush when I ate wheat or sugar and dd it was any amount of chili which would cause acid poos. They were in the bum cheeks though and obviously related to poo. Just thinking if it could be something in her wee? Do you take any medications or vitamins and breastfeed?

I'm sorry you haven't received the treatment you and your dd deserve.