What colour does directions lilac fade to?

Just a quick question if anyone at all knows. I have bleached blonde hair and have since last year. It's very light and my extensions are dip dyed lilac and I also have a lilac streak in my hair I did myself. It's fading quite quick because my hair gets washed more than my extensions. After 2 weeks its a silvery lilac colour. I know it's a semi permanent dye but I'm wanting to know if it kind of stains hair? I'm wanting to dye my whole hair lilac and I'm not bothered if it will just fade purely to silver or will it eventually fade back to my bleached blonde? Will I need to tone it out to get back to blonde or is the lilac dye working as a stronger toner since it's kind of turning silvery? You lot might not know but still there's a chance someone here might :)

My friend had light blue hair (im assuming it'll be the same) and it did turn grey rather than blonde again, you'll probably have to bleach it though. It's worth waiting for as long as possible just incase it does fade to a similar colour, hers was more golden blonde than bleached so it may blend!

Ah I probs won't go back to blonde anytime soon because I love the lilac. My hairdresser friend just told me it will fade to a whitey colour so think I'm gonna take the plunge and dye it all lilac :D