is there a dermatologist near you? I would recommend maybe seeing one with this - some are using promeris for demodex - demodex does affect puppies as it is from the mama dog and it is a sign of a poor immune system where the mites take over - here is some info on it and so sorry you are going through this and welcome to yt
Demodicosis (Red Mange) in Dogs Red, Puppy, & Follicular Mange (Demodectic, Demodex) in Dogs Demodectic Mange & the Immune System in Dogs
my friend is using benzoyl peroxide shampoo in her demodex dog are you shampooing with that? The face is tough though as you have to be very careful