As some others have said, since you brought up hitting yourself, she was probably just wondering if that's what the bruises were. Like to confirm that's where you were hitting. She also may have wanted to make sure they weren't from something else, like someone else injuring you. It could be she commented on them because you noticed her looking. But I understand your reaction to it. It's like if I'm starting to have a panic attack in session, I feel weird if my T points it out. I think I'm just so used to hiding things (anxiety, etc.) that I feel exposed when attention is called to it. You mention how you usually hide scars on your arms with bracelets, so I'm guessing it's that you felt exposed, especially because your T not only looked at them, but made a comment. I'd definitely tell her how it made you feel.