What does it mean when someone rubs their fingers on their eyebrows?

Well, to start, if you aren't causing yourself any pain or discomfort, it may just be a nervous tic, like some people that bite their nails or tap their foot. If you are causing yourself pain, or if you feel like you can't control it even if you try, their might be some more insidious underlying psychological or neurological problems (see Tourette's syndrome or Trichotillomania, perhaps?)