When your clothes come off....
Anyone I have dated in the pass I tell right off the bat. He will eventually find out so I figure I might as well tell him right away. "I used to be a fat girl" They usually dont believe me til I show them pictures. At least if they know right away there are no skeletons in the closet and if they arent okay with it - then they can hit the road ASAP.
Just my way of doin things.
MJ
Ok, I'm a married lady now, but switching my mind back to singleton thoughts...............It depends on how I feel about the guy. If he is someone serious that I plan on having a relationship, I would tell him before we got to the bedroom. Now if it was just something for fun, then what the heck does he need to know for. I wouldn't tell him. He probably wouldn't even notice. If he sees the scars and asks, then maybe, but I'm not bringing it up or anything. Oops , I just reread what you wrote....If this guy may be "the one," than i'd probably tell him before.