What on earth are those?

there are many possible causes. If it continues to spread, you'll want to get at the cause. In the meantime, I would just watch what happens with the lesions that you removed the scabs from. If they resolve, then removing the scab has been sufficient treatment. You can use sterile saline on a cotton pad to soften each lesion and remove the scab. No matter what it is, this treatment is safe and effective. Saline has antimicrobial properties and is balanced with the body fluids, so is a great cleanser. I would not put any medications on the lesions at this point. Also, until you know whether or not it is an infection that can be spread, use care to wash your hands and dispose of anything you use to clean it. Also keep your grooming tools cleaned after every grooming.