Manic Panic Creamtone Hair Colour Velvet Violet Pastel Purple Dye Vegan Purple by Manic Panic

Q: Does it work on black or brown hair?

It may work on lighter brown hair, but I don't think it will work on black hair. It works well on blonde, but as its a semi-permanent color it needs to be re-applied to keep color.

Q: How many boxes will I need for a 24 inch long hair?

My hair is about 4 inches long and I can get away with using half a container. So 3-4 to saturate 24in I'd think.

Q: can i put deep purple dream on my hair over my existing mystic heather? or should i bleach first?

i had green in my hair before and i just used deep purple dream on top and it covered everything. it came out very dark on my hair so it should cover mystic heather without bleaching as well. although if you bleach it the color moght come out the truest

Q: Does this stain your scalp

Yes, but only for a day or so. Try to avoid putting too much on your scalp, only for the stain factor. I don't bother worrying about it because it will wash off in a day or so.