I want to dye my hair purple (permanent) in a few days but I have a major problem. I've dyed my hair four times permanently before but whenever I would wash my hair a lot of the dye would come out and eventually, it would all be gone in a week or so. I've tried using cold water to wash it with and also colour protect shampoo and conditioner but it still makes my hair wash out. I really don't understand. I think I may have porous hair but I don't know what to do about it because I really like my hair purple and I don't want the same thing to happen again. What should I do?