I've had this happen to me... the best, fastest, cheapest solution that will do NO damage at all to your hair is to buy a semi-permanent color from th supermarket, i.e., Clairol "Natural Instincts" (my personal fave). Buy a shade that's DARKER than your highlights, but not darker than the rest of your hair. You can use it full strenght, or add 1/3 water to dilute, but either way, it works great and will NOT damage your hair at all. It will help all your color blend together if it didn't turn out even. Also, choose a "cool" or "ashe" tone (no "golden" anything) to tone down any orange in the highlights. This will cover your mistakes pronto and cost you all of $7! GOOD LUCK! Let me know how it turns out!