He CUT him ? and he's still bleeding ? Poor guy - I'd be really upset too. REALLY upset if I saw blood.
Most of us have had really bad haircuts but I can't say anyone ever shaved the girls faces - If that groomer has a yorkie I have to wonder what it looks like. But to cut him on his tummy ? That's like the easiest place to shave !
I would put him in clothes cause he probably does feel embarrassed....they really feel stuff like that and a cute little shirt will perk him up. Keep telling him how cute he looks too - and he'll be ok -