Many people will scream when I post this and tell you I'm crazy, but I would re do the whole thing today. I've dyed my hair every color that exists in nature and a few that don't. If I didn't like it when I washed it, I'd just dye it a different color. One memorable week, I was a blonde, redhead and brunette within 3 days time because I didn't like what I had done.
My hair never got crunchy or fell out or any of the other horror stories I've heard. Maybe I'm just lucky, but if I have another dye disaster I will redo it again the next day.