Nothing is permanent. everything will damage your hair to some extent. Go to a Hair cuttery salon plaza salon cielo redkin products are best. any redkin product not sold in one of those stores is out of date/ expired and DO NOT BUY IT. they will put price tag over date so you can't see w/o looking for it.
If you don't want to damage your hair then don't dye it at all. Neither is good for it. Though if you want something temporary and can change then wash out. If you want to live with a hair color that you are problem going to get bored of in a few months then permanent.