I recently went to a hair salon for hair colouring. The hairdresser who did it smudged some colouring on my forehead near the hairline. After colouring my whole head, he then clean the smudges away. After the next day, I suddenly saw a white patch on my forehead, area where the stains were. Went to see a demeterlogist, but he cannot really pinpoint the exact cause of this whitepatch. But I am quite sure it is due to the colouring or colouring removal cos it is at the exact same spot.

Has anyone experienced this before?