I have some rainbow-haired tales. I also figured I may as well experiment while I am younger. It was fun while it lasted, but I will say concerning bleach, proceed with caution, and/or investigate getting help with it professionally. I made the mistake of not waiting long enough in-between to bleach, and coloring too much in general over a few years and it completely ruined the integrity of my curls. My natural color is a medium gold blonde. My hair is relatively fine, even in its virgin state, so you can imagine what bleaching did to the strength of it.
Basically, the only way I could get it to look decent was to proceed to heat style it. DOUBLE whammy. In my experience, there is really no true return from bleaching, but there are precautionary measures one can take, as some others suggested.
I ended up chopping it all off and deciding to let my natural color and curls return, and I've been 'recovering' for about one year now.

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