How far do you go to avenge yourself?

Came across an article in the YOU magazine (2011) about a lady who was burned and disfigured horribly with acid (her eyes, face, and other parts of her body) by a man whose marriage proposal she had turned down. She won the case against the attacker, and was awarded a larger sum of money, which she turned down. In place of the money, she requested to be permitted to punish the man in the same way he had punished her, by dousing him with acid. While many people in her country supported her request, which was, by the way approved, there were just as many who did not, and felt the man still had human rights. It is totally understandable that she feels so strongly about bringing severe pain to the man who has ruined her life. I also do understand where the Human rights issues come in too though. But how do you draw a line between right and wrong? Did the attacker  nor relinquish his rights as a human when he made the decision to treat the victim this way? And isn't he now responsible for invoking such hateful feelings in this woman? How much can you do, should you do, before you take a step back, and bow out?