To supplement my earlier answer -I would probably not associate scars with self injury if I noticed them at all. I do not cut and don't know of anyone who has so I am not all that familiar with the sorts of marks left behind. I would probably assume some accident if I noticed at all (this is quite real that I just might not notice even were the person in a bikini - I could not tell you the color of anyone's eyes, or what they were wearing, or so on)