It could be a serious skin condition take her to the vet as soon as possible, I have a boxer and have never had this happen.
My Boxer Is Broke Out All Around Her Mouth With Blister Or Pimple Looking Bumps, What Can I Do For Her?
My doberman had pimple looking bumps on him. It was an allergic reaction to his water bowl. The bowl was plastic so we had to use glass or metal.