Diaper rash not going away

Hi, my baby is two weeks old and for almost a week now he has had a diaper rash that seems to be progressively worse. We’ve been using a barrier cream since day one. This rash is now starting to slightly bleed. We’ve been using Desitin as of yesterday evening with no improvement. On a sidenote, I think there’s a chance that I might have thrush but I exclusively pump so I’m not sure if I’ve given it to my baby. I’ve heard that can prolong a diaper rash, but again he hasn’t had any contact with my nipple.can someone recommend what we should do?