Uneven color

I have naturally darkish brown hair and I've colored it various shades of brown and the summer sun gave it some golden highlights, and my roots were showing. Between the coloring I've done and the sun, I wanted to even it all out. So I used a dark brown that have very blue undertones (when my hair has reddish undertones.) Now, I did a strand test on an under layer of my hiar and the results were fine. So I did all my hair and now it's more of a brown/blue color. Which I can live with, except there's one lovely spot that the dye didn't cover.Is this something that Dawn (keep hearing that helpss remove color) or Metalex/Uncolor can help? It was permanent dye. My main concern is getting all my hair one color.Thanks.