Sorry for this recto, all of the above is very invalidating. From what you are sharing here it seems as though your t is taking the tough t approach. Was she always this invalidating? Maybe she feels like this is the only way to get through to you is to downplay your problems. I absolutely do not agree with this approach but it helps some people to move on with their lives.
As for her not following up on anything, I know that some ts will do this because by asking you something it will be taking control of your session. I mean they prefer to let you lead the conversation and to hold a space open for you to talk about what you like to talk about. Sometimes a t has to try and leave their nosiness and curiosity out of therapy. It might come across as not caring but it is because they care and want the client to use their time as they need it.
I really do not like the way she handled your scars. This was you at your most vulnerable and it wouldn't have hurt for her to acknowledge that and try not to normalize them or belittle them. If you see her again, I think this is important for you to tell her how this hurt so much and how much you are actually hurting physically and emotionally. I think that if you or anyone is S/h they are in pain and the scars are only the tip of the iceberg the real pain is inside waiting to be seen and acknowledged.