Yeast infection???

My little one had a double ear infection and she’s been on antibiotics for five days. Her doctor told us to give her a probiotic to help prevent a yeast infection and we have been giving it to her along with her antibiotic. But does this kind of look like a yeast infection or is it just a diaper rash? I know what a diaper rash looks like but I’ve never seen one like this. If this is a yeast infection, do I need to call her doctor or can it be treated at home?