Step 1: Add Zipper & Select Raw Face Area
Once that's done, make sure you have a duplicate layer of the normal face. Then go to that duplicate layer, grab the pen tool and select the skin of the face enclosed under the zipper. I decided to do this part of the face separate from the neck - as the effect looked better that way. You can do it either way as you need to take the same steps to achieve the effects on both parts of the face. Once selected all the way around, then Right click, Make Selection (2 px Feather). There are a couple ways of doing the next step. To make things easier, we will then go to Edit, Copy. Then File, New - then hit PASTE to paste in this chunk of the face. Duplicate the layer.