Here's a test:

I'll keep a webcam recording myself during work for the next hour, now.

I will try to remind myself not to touch my face and will keep a tally sheet of how many times I successfully restrained myself, and often I caught myself touching it.

Then I'll review the video material and see how many times I've not even witnessed touching my own face during that hour.

[Just typing this post, I've already touched my own face 7 times]