You should either wait for it to fade out or get it trimmed off. Trust me, I'm saying this from experience, if you add too much color in you hair at one time, you'll end up bleaching the original color out of your hair(I still have the 3 colors in my hair: blonde, dark brown and pink though I kind of like it but thats not the point). I don't recomend it, it dries out your hair amongst other things.

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"Only reapers, reaping early. In among the bearded barley. Hear a song that echoes cheerly. From the river winding clearly; Down to tower'd Camelot; And by the moon the reaper weary, Piling sheaves in uplands airy, Listening, whispers, ' 'Tis the fairy The Lady of Shalott.'"- Lady of Shalott by Lord Alfred Tennyson