Cat going crazy itching and scratching?

Hello, following a grooming at the vet (shaving) my cat, he started itching and he keeps licking himself and sometimes scratching. He seems exhausted while/after doing so as I can see his heart is beating fast. It's his first time getting shaved and he acts crazy and keeps moving around and going under things ( I guess to help with the scratching) and lying down then walking etc etc. Can you please help me? Should I apply something like flax seed oil or lavender oil or something? I can't wait until monday to see a vet. I am worried for my little kitty :( I know it's not fleas or anything as I called the veterinarian and they told me they disinfect the area very well. And it only started after his grooming. Thanks!