Dawn,
You were right....or at least that's what the vet (dermatologist) thinks at this point.
Infected inverted nipple. So med's for now, if not better by Monday...then the vet will take it off and send it away to see if it's cancer. But for now, he doesn't think it's cancer.
By the way...found out that dogs don't have to have matching nipples on both sides. We had looked to see if there was another nipple on opposite side, but there wasn't.