There's a mod called Detailed Character Creation which allows you, among other things, to edit the appearance of any NPCs in the game, just like your own character (and adds more settings, but we won't need that here).
When you install it, it adds a button called "edit appearance" in the Encyclopedia entry for lords and the like. Open the entry for Abagai (N - Heroes - Abagai), click "edit appearance", then when the editor is opened, press Ctrl + C
It copies the "body code" that is currently in the character editor in your clipboard. In that case, it will be Abagai.
Paste the result in some txt document of your choosing and save it.
Now if you copy that code into the clipboard and press Ctrl + V when editing character appearance, it will change the character you're editing to that face and body.
Once you create a new save, you can use the Encyclopedia again to paste that face onto NPCs in-game (find Abagai again, open the editor from her page, then Ctrl + V), or you can use it in character creation to make YOUR character look like Abagai. Once you save changes and then save the game, the face will be set for that save, so you don't even need DCC active anymore. It doesn't carry over to other playthroughs, though, so keep the code saved.
There's probably a more optimal solution or a mod that returns old faces, but I'm unaware of such. If you have the save with old Abagai face, you just need to install the mod and copy her code, so that's easy enough as is.