Our Border Collie randomly got medium itchy bumps on his face last night, now acting really wierd.?

Our Border Collie, Cowboy, was outside playing yesterday in the yard, and about an hour after he came back inside, we noticed he had a bunch of medium sized bumps all over his face. They were hard bumps, and didnt feel like they had any fluid in them. We squeezed them and nothing came out. THey just got bigger. And they were just his face.

He could'nt stop scratching them, and so we got an icepack to put over them and it seemed to help. But as he scratched them, more and more bumps were coming up.

This morning, his face looks better, but right around his jaw/mouth, he is still swollen. But today, he is acting REALLY wierd!

He was eating his food, and with every bite, he acted like he was choking, and we checked, and there was nothing stuck in his throat. He wont go out to the vinyard to do his business. (there is a vinyard behind our house that Cowboy goes to do business in),

He is very hyperactive too, more-so than usual. He hasnt vomitted, no diarrhea, and has an appetite and is drinking as usual.

We have a vet appt, but i want to ask on here to see if i can get some suggestions to giv to the vet. (i work at the vets office as a Vet Assistant, so i do this anyways). But this is my baby boy and i cant think of anything other than red ants attacked him. :-/

Please, if you have an idea of what could've happened, or if something simillar happened to your pup, please respond.

Thanks!