Sorry to barge in from the beauty side lol!
This sounds like what happened to me about 8 months ago. My hairdresser knew I had a henna and indigo mix on my hair (good, high quality, 100% henna) but insisted that she wanted to make my hair look nicer by going much lighter, even blonder. She did 3 sets of strand tests from different parts of my head and put different volumes of product and she assured me all was going to be okay as the hair had reacted really favourably, texture and colour-wise to both the tint and the peroxide etc.
Prior to doing the foils she did a bleach bath - can't remember what volume she used. Then she put on the bleach foils prior to the tint and after about 15 foils, I told her they were burning hot - she hadn't finished doing them by this point, I only had 1/4 of what I should have had on the back and right hand side of my head. She opened them up and went white! Basically, my hair was dissolving in the foils! She rushed me to the back washer and my hair was coming out in handfuls in 5 different patches. It was breaking off midway down the shaft (I had a 15 inch long bob) in some places and about 1/2 an inch from the scalp in others. It went all shades of khaki, orange and blue with a few blonde bits. I was gutted. :cry::cry:
I knew henna shouldn't be mixed with bleach/lighteners but she insisted I was in safe hands after the strand-tests. Metallic salts products and lightening products certainly didn't make for a good experience for me.
Sorry to barge in. It's totally shattered my confidence and I'm grateful my eldest is starting Level 2 Hairdressing in September, :hug: as by the time she finishes all her initial training in two years, I might have got enough confidence to let someone else loose on me again