AHHHHHH!!! Thank goodness your friends going to help you out! I had bleached out hair for about five years... and im talking like pamela anderson white hair. I had a friend of mine dye it a dark auburn ( close to my natural color) about 2 years into my blonde-arexia, because i literally looked like a scarecrow was growing on my head.. well, that didnt last very long and about 2 months after having my hair dyed darker, i decided i needed to bleach it again, at home. It was a horrible, horrible decision. Not only did it burn so horrible, but my hair turned a terrible orange highlighter color and broke off about 2 inches. I had to pay almost 300 to get it fixed at a salon. It was hair 911. If your hair is already died, bleaching it at home will not just lighten the color but react with the undertones of the dye that is on top of your hair follicles already.. being that my hair was died a red tone the bleach lightened everything into a very very warm orange color... if your hair was virgin, it might react differently... but good job getting your friend, a professional to take care of it and congrats on your wedding!
<3<3 MAKE LOVE- NOT WAR<3<3