Hair can be dyed twice in one day, but it may experience severe damage. Every time hair is dyed, the moisture is stripped from the hair follicles. This can worsen if it is dyed too often.
When dying hair frequently, there may be more breakage, dryness and split ends. Wait at least a few days, but preferably a few weeks, before attempting to dye the hair again. Use a deep conditioner after each hair dye application to replace moisture. Continue using a special conditioner every time the hair is washed, as recommended by a hair stylist.