I do know that majority TV actors have a clause in their contracts that state they cannot make any extreme changes to their appearance--including their hair, without written permission.
On OLTL, Kassie DePaiva (Blair) got permission to cut her hair. The day before her appointment, the writers got creative. They wrote this masterful revenge scene where Skye drugged Blair and hacked off her hair. 🤣
And then there is the Keri Russell/Felicity chia head incident. Which is a bit of a reversal. KR sent the producers a pic of her in a wig, with short cropped hair. They then floated the idea to her of cutting her hair. KR went for it and overwhelmingly, fans did not like it. I know I didn't. Her haircut is blamed for the ratings drop in season 2. LOL