Hi, some of my npc's that have had a makeover from a mod have the black face.  Now I use a lot of npc makeover mods such as Improved Bards, The Ordinary Women, Bijin Series of mods, Bards of Solitude, Ladies of Whiterun, Ladies of Solitude, Ladies of Dragonbridge , and Pandorable's NPC's Dawnguard.   The mod that is causing the black face is Pandorable's NPC's Dawnguard.  I have that mod loaded last in the load order, and I've reinstalled the facegen files in case they were overwritten