Is there any way to make a hair dye come out lighter than it should?

Not really, the advice I have would have been to bleach some parts of your hair and not bleach others... so the color will be darker in some spots and lighter on others. You could try leaving it on the amount of time specified for half of it... wash it out and dry your hair, then use the remaining hair dye and leave it on for less time so its lighter. It really depends what color ur hair is naturally as well...