Dark Face Bug
If a new NPC is created or the face of an existing one is edited, then the "dark face bug" is introduced into the mod. The actor with the new face will have a darker skin color on the face and head than on the rest of the body. there will be a sharp neck seam line between the two colors of skin.
In Oblivion modding, editing existing faces on NPCs or creating new NPCs could be performed without having this problem.
To solve this problem with dark faces, a procedure much like this one will need to be performed:
(1) Open Wrye Bash and .esmify the .esp. Then load it again in the CK.
(2) Select all the actors added by the mod or that have faces edited by the mod.
(3) Press CTRL + F4 to export facegen data. (It can take awhile to process.)
(4) Use Wrye Bash to .espify the mod again.
The mod will now have meshes and textures associated with it that will need to be packaged and uploaded along with the .esp file. Failure to do so will mean that all gamers who download the mod will have the dark face bug when they use it, even though the problem no longer occurs on the computer the mod was built on.
The directory locations of the mesh and texture files that will need to be packaged are like:
My Installation Directory\Data\Meshes\actors\Character\FaceGenData\FaceGeom\MyNewMod.esp\000012C4.nif My Installation Directory\Data\textures\actors\Character\FaceGenData\FaceTint\MyNewMod.esp\000012C4.dds
It is thought that maybe the .tga files that were also generated serve no function and don't need to be uploaded with the .dds files.