I've had blonde hair (colored) for the last 20 years. I tried a new colorist, I asked her to make my hair a shade darker then what I usually have and to add highlights. Results, a full head of white hair. I freaked out and returned the following night, only for her to add a color over the white hair, Now I have a muddy look, hair color that is darker then my natural hair color. I'm using a harsh shampoo to try and pull the dark color off the white color. What should I do??

Did you tell her you don't like the result? Eek I'm sorry about your experience. You can try using clarifying shampoos but that won't completely lift out the colour. The only way to lift it out is by using bleach but your hair might in bad condition right now?