Ask a Psychiatrist and Get Answers to Mental Health Questions ASAP
Her behavior towards you may be premeditated or it may be a defense mechanism. If you see that she's acting as though you never existed, that could be her way of dealing with her feelings (whatever they are) and with the fact that the two of you work together.
In order to be able to move on, it would help not to feed into her behavior at the moment. What she had done in the past is in the past. Try not to personalize her actions because the more you do, if she's volitionally trying to aggravate you, that would empower her more as a result of your reaction.
As far as exposing what she's done in the past, that would not necessarily allow you to move on as you're going to be opening another can of worms. It would also make you seem as the aggressor and she as the victim. To be able to move on, you'd have to accept what had transpired between the two of you both the good and the bad times, work on forgiveness and in dissociating your thoughts from her now. Meaning, whatever she does, try not to become consumed by it. There may be times you'd want to ignore her and just interact in a professional neutral manner. You'd have to remind yourself that you're going to a place to do a job and that your goal is to not become distracted by her behavior. Her goal may be to drive you away from the job. When you see her everyday remind yourself that this is an individual from your past who had made mistakes like any other person and resolve to stay grounded in the present time. You'd have to monitor your internal dialog because at times you can become consumed by things just by the nature of your thoughts if they are negative or you're personalizing these. Moving on emotionally is a process and you should not push yourself; rather allow yourself to take it one day at a time and do your best during that day to be in control of what you think, what you feel as a result of it and what you end up doing. Your goal is not to stoop to her level by exposing her past. She sooner or later would have to face her past herself.