CHANGING SHADOWHEART'S HAIR BACK:
If you want to change Shadowheart's hair back to her original color/style in Act 3 after she dyes it white you can. I only know how to do this in Windows, sorry console players.
First you will need to launch the console command line window when your game starts. To do that you'll need BG3 Mod Manager. Follow this guide to install it. Make sure you do all the steps so you check off LAUNCH console at game startup.
https://wiki.bg3.community/en/Tutorials/Mod-Use/How-to-install-Script-ExtenderOnce you launch the game with the console you will need to run the following
code in the game AFTER Shadowheart changes her hair style/color.
ALT-TAB out of your active game and go to the console window. HIT ENTER a few times until you see the S>> prompt.
Then copy/paste the following code into the console and hit ENTER when done:
-- MAKE SURE TO RUN ALL 3 COMMANDS
Osi.RemoveCustomVisualOvirride("S_Player_ShadowHeart_3ed74f06-3c60-42dc-83f6-f034cb47c679", "e05b0f79-d3af-41eb-b0b2-1164b6f0debf")
Osi.RemoveCustomVisualOvirride("S_Player_ShadowHeart_3ed74f06-3c60-42dc-83f6-f034cb47c679", "c7f78eb7-6858-4f02-836b-d8c8b56c34fc")
Osi.RemoveCustomMaterialOverride("S_Player_ShadowHeart_3ed74f06-3c60-42dc-83f6-f034cb47c679", "831f8c8a-4101-4265-ad55-1a57217d2af7")
That's it. Shadowheart's hair will go back to the original. As far as I know you cannot turn it back to white, so make sure you save your game first if you want to go back. Of course there are MODS to do this but this is directly built into the game.