Just because Skip talks himself up doesn't mean he is 100% right all the time. Take his teachings with a grain of salt, as you would with anyones advice off the internet.
I think a vet visit is the only way to know for sure. If it was an isolated incident and you never see it happen again, perhaps the snake was spooked by something or angry.. who knows. I wasn't there for sure, but it could have just been a very angry snake, no necessarily a sick one.
Just my opinion. I'm no vet!