Draco's teeth ground together for a moment while she spoke. It was clear she'd figured it out. It was dangerous that she'd figured it out, and if she had then who else hadn't been fooled? At least if they'd noticed or guessed, they'd known enough not to say it to his face, but she...
And he should have been angry, or insulted. He should have at least been able to feign those things. Instead he grit his teeth again, but then after a moment's hesitation, unbuttoned the cuff of his left sleeve - pushed the fabric up enough for her to see. The scars from the accident were gone now, thanks to Snape's salve. All that marred his skin now was His Mark.