T.F.
I have not heard of this before, I but I do suggest that you don't mess around with anything that seems involuntary! Start with a call to your pediatrician and see if they want to see him and/or recommend you contact a pediatric neurologist. It may just be nothing, but why take that chance??
Also, my cousin's husband is a neurologist and when they were here visiting a few weeks ago, he was saying that they can now take a skin biopsy and find out a lot about what's going on neurologically that way. It sounds strange, but he said it was pretty fascinating that they can look at the nervous system now through the skin and sometimes find things they don't pick up in brain scans.