1. Download and install Ellise's mod: https://www.nexusmods.com/dragonage/mods/4666/
2. Download this mod's (Zevran face textures) archive,
3. Extract it using any program (7zip, WinRAR, etc.),
4. Open this mod's (Zevran face textures) archive,
5. Copy (Ctrl + C) the *folder* named "Zevran textures (Ellise and khisartin)" and paste (Ctrl + V) it into
*\Documents\BioWare\Dragon Age\packages\core\override\
6. In Unique Face Textures for Companions (el_companiontexturesDAO), you should locate those files:
*\Documents\BioWare\Dragon Age\packages\core\override\el_companiontexturesDAO\el_textures\*the files are here*
pn_eye_elZevran_0d.dds
uh_hed_elZevran_0d.dds
uh_hed_elZevran_0n.dds
uh_hed_makazevran_0t.dds
uh_hed_stbzev_0n.dds
7. Either delete those files or move them to another location, should you want to revert the changes.
For example, create an extra folder in *Documents\BioWare\Dragon Age\packages\core and call it "backup", so you'll have:
*Documents\BioWare\Dragon Age\packages\core\backup
put Ellise's original files here
*Documents\BioWare\Dragon Age\packages\core\override
this is where all of your DA:O mods are located
*\Documents\BioWare\Dragon Age\packages\core\override\Zevran textures (Ellise and khisartin)
this the new textures, an easy to remove single folder
That's just an example. You may just delete the abovementioned files, without backups.
8. Done!