Originally Posted by
cava
A vet usually. They might also sell it behind the counter at human pharmacies. (They do in my area, at least.) You're looking for a cat/kitten dose (not dog) and you'd use ONE drop out of the pipette or you can draw it up into a 1 ml syringe and put ONE drop out of that, on the back of the neck. It get's absorbed through the skin and works all over, not just the place you put it.
The triple antibiotic ointment on the ears will help to avoid a bacterial infection develop on any open skin, and may also be soothing, but it doesn't treat the mange itself. But it's a fine add on treatment.