I read the reviews and some mentioned that it either didn't work or it had trouble tackling areas with thicker hair on the face.
Well, to be honest, it didn't work for me on the first day, I tried again and again, trying to handle it in different ways until I accidentally stumbled upon the most effective way to use it (for my own face). So I think it just takes a bit of time to get used to, for me it was to lay the whole thing flat on my face (while bending and doing the motions mentioned in the instructions), I think this increases the chances of you griping the hairs and pulling them out, whether they are thick or thin. Don't give up! It was damn painful for me, but well worth it :) now I feel more confident about my upper lip area.