Hello everyone Can you recommend what this is? It's been almost a mont…

Hello everyone Can you recommend what this is? It's been almost a month since it started, we went to the pediatrician and they said it was perinatal dermatitis. We applied zinc ointment, Bepanthen, Sudocrem, and creams from other brands didn't help. Changed to other brands of diapers It got even worse, straight up red all over the bottom and also on the back Sometimes it goes away but then reappears. I don't use wet wipes every time I change a diaper, my bottom under running water