This happened to the larger of my 2 yorkies (although she is only 8 lbs) and I flipped out. I called and said I wanted my money back and I would never come back. I got a refund and the owner personally promised me she would be the only one grooming them from now on.
My smaller yorkie got groomed today for the first time ever (at the same place) and I was extremely happy with it. I dont see a single razor burn, cut, rash, nothing.
Just let them know....they need to know. Ask for the owner or manager. Sorry that happened to your baby....keep an eye on it and watch for infection.