I Feel Like Such A Horrible Mother

So my 9 month old has developed a severe yeast rash and I do not know how I change her frequently and with every change I apply lots of A&D; to protect her from this. My mother praises me for having a 9 month old who has never had a yeast infection and now she has one. I’m so embarrassed I haven’t told anyone. I’ve been trying to deal with this on my own but nothing is working. Does anyone have any tips or suggestions? We’ve been to the doctors and it just hasn’t worked. Im thinking about bringing her back to the doctors but I just feel like I’ve failed as a parent. 😪