My Lab Casey

I just got home from work and he's acting very weird. He tried to dump but couldn't.
I got him back in the house and looked him over.

His scrotum is swollen and is about the size of a small red grapefruit and looks like one to.

What the heck did he do while I was at work?

Hernia? IDK

I called my buddy who is a vet so sometime tonight he will call me back.

Thoughts?