Two months ago I bleached my hair to a light blonde color, and then dyed it with a medium ash blonde hair dye. Well, my hair was the ash blonde color that I wanted on top but the rest of my hair was an ashy gray-like old lady gray.

The gray eventually washed out after about a week leaving the color that I wanted.

Now my roots have started to grow in and I want to touch them up, but I am afraid of my hair turing gray again. How can I apply the haircolor so that it doesn't turn ashy? I want to apply the color to the roots of course but I also want it to blend with the rest of my hair. How long should I leave it on the previously dyed hair?

I have also read about putting on a protein filler first prior to dying the hair, but I am not sure how to use it.

Any advice would be appreciated!