I've experienced this problem for quite a while now, and I'm more than certain that this is a lighting problem.
I have FCO installed and have an ENB. This problem occurs with the hairs of my character and other NPCs alike.
I'd have extreme gratitude for anyone who could help.

(Look at the eyebrows)

Spoiler:

do you have the same issue without the ENB installed? if not i'm pretty sure it has to do with FCO, as with the more recent version of the mod eyebrows are added onto the character as separate "head parts" (similar to facial hair). do you mind linking me to the ENB? i could try fiddling around with the files and figure out where/what the issue is

Okay going to plainly just state it's the ENB first off. So basically there's an issue where the irregular shine comes from is usually facial hair, sometimes even with regular hair, but that's fixed already with this mod:
https://www.nexusmods.com/newvegas/mods/50285/
(Some ENBs have the SSAO hair transparency/transparency fix which sometimes doesn't work personally, but try it anyways.)

Now first off you're using FCO, which gets a pretty bad rep, but sadly sometimes ENB presets don't work with mods that edit sh*t visually, especially hair and weapon textures, I've had some hair looking like it's harnessing the nuclear energy in the atmosphere with how much it was shining.
Also make sure you have when you installed FCO (through the installer) with the ENB option checked, this could probably cause your hair to look shiny. Other than that, it's probably your ENB settings, in which I'm not entirely sure what to tweak to edit the glowing of your eye brows without editing something else visually.

Hope you solve your problem, take care.