It is best to wait several weeks before dyeing hair again. Over-dyeing can cause permanent damage to the hair and scalp.
Coloring hair takes a large toll on its health. It can break or die if too many chemicals are used. After coloring hair, wait about 4 weeks to redo it. If the hair is not healthy and prone to breakage, 8 weeks may be a better time frame. If the hair is being dyed darker, recoloring may be done a little sooner since the process is not as harsh. Lightening or bleaching hair is a lot tougher on the hair and scalp and can cause more problems.