I have a huge scar running down the middle of my back from an injury (don't ask). Do I just introduce myself by saying, "Hey I'm Diana, I have a huge scar running down my back."? No. The point is that unless they see it or ask about it, I am in no situation where I need to tell. Even if they ask, you don't have to tell if you want to leave your past behind. It's completely understandable. Everyone has their secrets and they have the right to keep them.