I have dark brown hair that is turning gray that is dyed brown obviously to cover the gray Can I get hightlights lowlights instead of redying my whole head again?

yes get an all over colour to get rid of greys then get highlights through new base colour.When your greys reshow get a shade lighter in brown to cover these ,the highlights will cover the fact your roots are a diff shade from the rest of your hair .This should gradually lighten your base colour