Who Are You Now?

10 years after the final battle of Hogwarts, living their own lives and finding their own places in the new world, Severus Snape gets a call to help fill in. He never expects to see someone from the past he tries so hard to forget. Can he lose the mental image of his student from all those years ago and see her for who she is now? And can they figure out her scars? AU Sorta Songfic