Kind of diaper rash

Si

(Not my picture) My daughter has this exact kind of diaper rash. It will NOT go away!!! Aquaphore, butt paste, Desitin and now we are using nystatin left over from my moms prescription for it (only for about 24 hours) and it hasn’t made any improvement! She has her check up Tuesday so I’ll definitely bring it up then but does anyone know what this is?! Is it a yeast diaper rash? Any tips on how to get it to go away?