Sorry this is late. Yes, I have looked and scrutinized back and forth in the nifskope, blender and fallout's data folders but apparently, still no success but well I learned stuff along the way thanks to that. I've found out about normal_maps and what it does soo maybe it's the reason it gives the character some moustache-bump above the mouth for it to create a dark moustache shadow illusion. Also, the issue wasn't from the downloaded mod as it exist already even in the vanilla. They've been around years now. Take a look on Moira Brown on No. 7 FUGLY!: The Ugliest Video Game Characters of All Time – OC Weekly to give you some image clue.