tipping in a salon PLEASE HELP

I just got my hair highlighted a darker shade and it is turning a funky color. My stylist is fixing it for free b/c she doesn't like what it is doing.  It cost me $90 and I tipped her $20. 

Do I need to tip her again even though she is fixing her mistake for free???? I love my stylist and don't want to make her mad, but I also should not have to come back in for her to fix something...

No. If she's doing it for free, it's because she recognizes that this fix is part
of the first color. You've already tipped her for this. She probably feels bad,
and if she has pride in her work, she wouldn't take a tip.

If you go back to her another time after this and you feel comfortable,
mention it to her. (It would be awkward this time.) Tell her that you like her
work, and you always tip her, but that it didn't feel right to tip her when she
was fixing for free. I'm sure you'll get her opinion then.