That is silly. You run alot of risks bleaching your hair alone. If you use bleach and get any of it on previously bleached hair and not just the roots you can have breakage. If you choose to lighten with a color, your have to be very sure that your hair will lighten without the use of bleach. That is why bleach was invented...not everyone can lighten with just color. And you need to have the knowledge to remove whatever you use at the right time so your roots match the rest. When the roots are covered in chemical they can look lighter than they actually are and you are removing it too soon...that is why some people walk around with yellow or orange areas at the root.Using a lightener is not like covering your roots with a dye...it is much tricky and worth a professional being involved. Because you are now dreading, if you lighten the hair incorrectly you run a huge risk of weakening the hair. Since damage to hair is cumulative, you may go on for awhile thinking you are fine until some dreads start breaking off. There are certain instances that need the attention of a professional and not ruining your hair can be worth the money. If you go to a real professional asking for a touch up ONLY, they should be happy to comply. Please reconsider doing this yourself