I recently dyed my hair to a shade of red like 3 weeks ago. I had brown hair before and the shade change wasn't that dramatic. Im thinking that when it comes time to re-dye my hair I want to go a few shades lighter. I want to just do a box dye, but I was wondering if it'll work. Do I have to bleach my hair to get the old color out, or can I just dye over it? I really want to avoid having to pay to get it done at a salon.