Yeah... I've S.I but don't have any scars. Although logically I know than anyone can recover from self-harm and that it shouldn't matter if they're old scars and actually a sign that a T has been through stuff and come out the other side... I dunno, it would put me off a bit. I think I need to think/know that my T is strong and capable and has enough ego strength for the both of us.
It would matter less if I saw the scars once a trusting relationship was established, but if it was a very new T, I think it would bother me, rightly or wrongly.