That does look like it could be staph. I seriously doubt she got it from the groomer. Something made her itch ... maybe a shampoo the groomer used? Just a guess. There is hair there, so clearly it was not irritated from clippers.
Anyway....staph bacteria is found on nearly all dogs' skin. When they lick and/or scratch then it gives that bacteria a place to invade. That is how they get these infections which are actually quite common. You said she was licking and scratching, so my guess is that is how she got it.
I cannot even count how many times over the years I have dealt with staph infections in dogs. Usually it happens to allergy prone dogs because they scratch and/or lick themselves. It is not contagious to humans! I sleep with my dogs and have never seen an infection from one go to another dog nor have I contracted it! My vet assured me of that the first time one of my pups had it.
To make yourself feel better, put a call into your regular vet.
