My daughter did something similar aged about 6. Facial "scrunching " is a very common tic.
When I finally realised it was a tic I pieced together that actually she had others but we had never noticed.
I thought she had a urinary infection when she was younger but actually her stomach muscles tightening was a tic.
She also regularly flexed her hip ( sort of dipping when standing up) - all very documented tics when you look into it. All rhythmic , repetitive and quite sudden movements. But all that you wouldn't really see unless you were looking.
We took her to our local GP - who didnt really know very much - and referred us to a paediatric team at our local hospital ( London area) when they read the case they said no point in us seeing send to consultant neurologist.
She was great - and has seen us 3 times now over the last few years. She simply watched my daughter chatted to both of us and confirmed what we thought.
The consultant said they do not medicate unless it interferes with life drastically.
She said they are currently trailing CBT ( there are some programmes at Great Ormond Street) aimed at children aged around 11.
Seeing the consultant helped my daughter understand it a bit better and also be able to talk about it.
It also meant we had paper work to show the school to ensure they allowed her to fidget (!) We had a SENCO assigned and a counsellor just to keep an eye on her.
She is ok with it all and some days you wouldn't notice anything as the tics wax and wane.
We notice an increase when she is tired, stressed or needs the toilet.
All of these things now the school knows they have been able to help us.
Hope that helps !