Try Honest Company diaper cream. NEA recognized for eczema prone skin and fragrance free and it is a gentler option for very sensitive skin while still providing a protective zinc oxide barrier.
Apply a thick layer to clean, completely dry skin at every diaper change and an extra thick coat before naps and overnight. Use lukewarm water or fragrance free wipes, allow 5-10 min of air drying, and avoid rubbing. If the rash is not clearly improving within 48-72 hr or shows bright red patches with small satellite spots, contact the pediatrician.