Will my dogs hair grow back after treatment for mange?

My dog has a few bald spots on his body. He is going to get treatment for mange but I was wondering if he will have those bald spots permanently.
This is our first dog and he has always scratched from day one. We have been giving him flea medication also from day one. He started with 2 small bald spots on his leg and we thought he might have scraped himself while playing in the yard. However, more spots started to appear and we finally took him to the vet.

My understanding is that his hair will grow back with time and healing. I’ve heard of some really bad cases where pets have lost 50% or more of their hair, and have had a full recovery, but it will take time… sometimes weeks or months depending on how bad the loss is.

I’d like to ask you a question in return, if you dont mind…
What was the very first sign you noticed, that your dog had mange?

I’m actually researching this very issue, as my little chihuahua has had a horrible case of the ‘itchies’ for over a week now, but NO other signs. No hair loss, no sores, no rash. But definitely intense itching. So much so, that she’s waking me up at night. I’m so sad for her, and I’ve already treated her with Revolution, but no relief. She just keeps scratching and biting at her hind-quarters. Thank goodness… not so bad to make herself bleed.