I've been struggling with the grey face bug on my game's existing human NPCS for months now.

• I've tried exporting facegen data with Ctrl+F4 (not an efficient task on my slow computer)
  
  • for all NPCs,
    
  • or just Nords,
    
  • or just Redguards (the ones most visually affected by this),
    
  • or just particular NPCs of these races.
• I've tried setting the interpolation value to 0 for some NPCs in the CK and seen no change once I'm in game (yes, the mod is last in the load order.)
  
• I've used the setnpcweight fix in-game on my companion, only to have the grey face reappear as soon as we go through a load door.
  
• Last night I uninstalled every texture from the texture/actors/character folders that pertained to humans (bretonfemale, bretonmale, female, femaleold, etc.)

I'm completely at a loss. Does anyone have any further suggestions for what I could try?

...of course, after I spent all that time trying to figure it out, I google it one more time and find out that it's because I have Expanded Eye Color Selection installed. *sigh* Well, hopefully that'll help somebody else. This can be locked

I'm glad your issue has been resolved.

Locked per OP request.