That happened to me before. Not fun right? The best advice I can give is to wait a week or so and during that time do a few deep oil things for your hair so it won't be all dried out. When you think that your hair isn't going to be ruined if you put more dye in it , then try using the same or a slightly different blond to dye your hair again. That should take away the yellow or brassiness and make it blond. Another way is to try to blend it together by adding some streaks. I do not agree that you should always get you hair colour changed professionally; I think that store bought dye that you can do yourself if just as good as at the salon, plus it saves you time and money. Hope this helps.
