Never go lighter than your own skin color.
last time i had multicolored hair, i bleached the crap out of it. turned it platinum blond. then i dyed it the color i wanted. which was electric blue at the time =)
Just beware of yellow or orange its happend to me a few times
Time and cutting the busted hair off will even things out. You have to pay thousands of dollars for the work of a person skilled enough with coloring to do it acceptably. Patience.
remember if your going to bleach remember its extremely harsh on your hair so make sure they do not over do it. Also lots of conditioning the leave in type.