Happily, I do not have medium-dark brown blotches all over my face. I managed to avoid getting any on my skin to leave unsightly stains.
For those curious, I have done the facial-hair-dying for a show in the past (actually two consecutive shows), but both were in college. "The Elephant Man" and my "on-stage for 45 seconds, say nothing, and get frogmarched down a flight of stairs with my hands cuffed behind my back" role in "A View From the Bridge" (they needed a couple extra bodies...I used darker makeup and played an Italian)