Any help is gladly received :)
Most Helpful Guy
To my knowledge, the difference between regular dyes and semi-permanent dyes is that you can't simply wash out the latter. The people you talked to online were bullshitting you, because your hair will go back to it's natural color, it's just that depending on how close to your roots you dye it, it could take a REALLY long time.
The only way to completely get back to your natural color is to just keep getting your regular trims and wait. New hair will grow in your natural color, so you'll just have to keep trimming until all the dyed hair is cut off and the natural colored hair has replaced it.1
Most Helpful Girl
That's online scaremongering. Dye only affects the part of the hair outside of your scalp. Any new growth will be your natural colour.
Semipermanent dye eventually washes out, to the best of my understanding. If you're a very light blonde your hair can be "stained" by a bad dye job and require a lot of processing by a skilled professional to fix it - but it will still grow in the right colour.1