Yeast diaper rash?

Meg

Hi! My son just turned 13 weeks and is on an antibiotic for a uti. He developed this diaper rash and it’s been days now. Nothing seems to be helping much; Desitin, Aquaphor (both the fast relief diaper rash cream and healing ointment), or the Honest Diaper Rash cream. I’m now thinking is it something more? Please and thank you for all the advice.