One of the best t's I ever worked with admitted to a trauma history within the first two sessions. He was also very open about the struggles he had overcome, and the ones he still faced. He made it very clear that he had worked hard to get where he was. It was a relief to know that someone actually understood what I was going through intimately... that said, if my t was unstable (or I felt they were unstable) at the time, I would feel the need to take care of them and not say anything that may trigger them.
I would have no issues with scars, but I would need to know t was stable...