Worst diaper rash I've seen

Hi all, Dr appt Friday but thought I would ask in the meantime.

I've tried desitin, bourdreax's, clometrazole (lotrimin), bacitracin (when he was so raw he was bleeding), airing him out, baking soda baths, changing wipes etc. I also pat him dry before applying any cream so that I'm not trapping moisture. Now I'm just trying plain baby diaper cornstarch with aloe incase I've overdone the creams! :'(

Any hints or have you seen this on your baby before? He is 22mo old.

{Edited by Glow}