I'm not sure if my kitten had ear mites when I got him at 10 weeks, but he was born on a farm so got a full bath and grooming treatment when I took him into my place. I bought the ear mite treatment right away as he had really hard/black/dried crust in both ears, which is the signature of ear mites, dried blood. He never scratched his ears and was a happy kitten…until I started treating his ears.
When I would clean them, he would scratch like it itched and for 10-30 minutes after. I can imagine they hurt as he would scream when I was removing the gunk from his ears. I felt really bad, but it had to be done, my sister who is a vet tech says it sounds like he had mites and sometimes if they are used to them, they won't scratch their ears. It took about 2 weeks of me treating his ears every other day before they started to look better. Now his ears are perfectly pink and crust free! It worked perfectly.