How to remove bleach blonde from hair?

basically about a week ago i let one of my sisters friends dye my hair, she was doing it for a course at her collage . she didn't show me how she was doing it but she said she used bleach blonde and now my hair look like hay and it fall out :s . not Very good. i usually go to shear beauty to get it done and only highlights so ive never had this colour all over before. it Very horrible. dose anyone know how to remove it without coloring over. just want it back to normal . never trusting a college student again. (although some are good) . please help. thanks