Ok I colored my hair dark brown a few months ago and now I have 2 inches of outgrowth which is blonde. So I wanted to color my hair black cherry I start from my ends and worked my way up and now my roots are bright dark red and the rest is just black, you can barely see the red on my ends. What should I do? I wasn't sure if I should color my roots the same color but with 10 developer for about 15 - 20 minutes