Small bumps on Dogs head a bad back after grooming

I was petting my Great Pyrenees after she got groomed from a new groomer and noticed a significant amount of bumps on her skin (more on the second day). Specifically on her head and he back. You can't see them but you can feel them and they seem poppable if she chewed at them. I'm wondering if it is razor burn or something more serious? I called the ER and they said to just try over the counter rememedies until the vet opens ina couple of days.

I would send a pic but you can't really see the bumps even with the flash.