Potential seizure?

My juvenile Nic Boa was just sitting on top of his hide, then he slowly coiled his neck back (from his head to about 1.5 inches down), and his head just violently twitched for about 1 second. I don't even know what else to say, I just want to know if he's alright.

Has this happened more than once?
A one second twitch doesn't sound like something to be worried about IMO

It's only happened once, but it was the violent movement that really concerned me. I know of a vet that I can go to if necessary, but I just thought I'd ask here first. He's shown no other signs of sickness that I'm aware of, he eats well and is well-hydrated. He's also always in my line of sight, so when I'm in my room I always see him.

I would expect a seizure - rolly polly movements, unable to control the body, twisting around.
I've seen a small head twitch before, or like if you startle them and they pull their head/neck back quickly sometimes the head shakes a little. I would not consider that a seizure.
Just keep an eye on your lil one and if it continues or you see full body spasms, then that might be cause for concern. I'd recommend trying to get it on video that way you can show the vet what is happening.
:gj: