Hi, I have been dying my hair for a good 6 years now, I'm 19 with curl type 3b but sometimes it varies between 3a and 3b, which is in fact because I've dyed my hair so many times. I almost ALWAYS use dyes from sallys now just because I like the selection better, I just recently bleached my hair because I wanted highlights and the parts that are a lighter blonde, red color dont seem to curl as well as the rest, looking back at old pictures from when I was younger, my hair is a lot less curly and a lot more course now. It honestly has nothing to do with whether or not it is a box dye or from sallys. If it's permanent color, chances are it WILL damage your hair. My advice to you is to not bleach your hair at all, and if you must dye it, try some semi or demi permanent colors because they have less chemicals and you can actually experiment more. Or even henna dyes which you can find online!!