I'm surprised your vet had you start Ivomec with Lola only having a mild localized case of Demodex. Usually vets will try and "wait it out" to see if the pup's own immune system can overcome the mites. Sometimes dogs can "spontaneously recuperate" from localized Demodectic mange. I've seen two cases of that before.... But, as with almost anything, views and oppinions (even in the medical/veterinary community) vary. Plus I do seem to remember you saying something about the vet having done a skin scraping and it was loaded
with mites and eggs. Sooo... that's likely why he had you start the Ivomec.
I'd give it at least a month's time. Hair does take a while to grow back in.
What dosage does the vet have Lola on? (How many micrograms per kilogram of body weight?) Was he wanting to wait the full two months before doing another skin scraping, or was he going to check again in just a month?
Hope Lola gets to feeling better soon. And gets her hair coat back!