I have no idea why you think this is a thing, but just in case I subconsciously tend to do this, I set a timer for 2 minutes without touching my face.

It was effortless.

Edit: wait, I've been in an MRI machine for over an hour where I can't move my arms from my side. How can you think one minute is anything?

You clearly have superhuman endurance and I bow to you.

This video says that the helmet mic serves as a decent face scratcher: https://www.youtube.com/watch?v=5VCuaZCRn1U

I've also read that many astronauts put strips of adhesive Velcro in their helmet for this purpose: https://space.stackexchange.com/questions/42012/nose-scratch...