My HA started with this symptom. It can be very disturbing to see your finger(s) twitch and move - I know firsthand (no pun intended!).
I truly let my associated fears ruin an entire year of my life. My associated anxiety grew, and caused more symptoms, and those generated even more fears -- It was a terrible cycle. And yet I am fine! Totally healthy except for, of course, ANXIETY.
Please don't do that to yourself! Just let it go. Don't look for other possible underlying causes ... Don't self-examine ... Don't google (for the love of God!). Just let it go.
It truly is extremely likely to be absolutely nothing - in fact, even it is probably a symptom of your anxiety (even if underlying and not perceived directly).
It can be hard to have small children. It is a lot of responsibility and can stir up all kinds of fears in us - fears we might not even have realized we have. Be kind to yourself, take care of yourself alongside your care for your family, get out of the house so you realize that life still goes on despite your fears, and -- treat your anxiety.