I am going through the same thing. When I was in high school, I got my hair done once a week at a salon. I would get it washed, deep conditioned, blown out, then flat ironed. That went on for about two years every week, and I was natural, but alas, when I tried to wear my curls, they wouldn't curl. There were flat, limp and lifeless straight pieces, with my whole left side completely bone straight. I have tried consistent deep conditioning treatments, protein treatments, everything! So now, I am just growing it out. I've learned to deal with it and the heat damaged parts aren't breaking off, so I am just going to keep that up and gradually cut it away.