"Artery, I assume," he says, disinterested. "Definitely toxic, possibly with magical enhancement. There was some swelling and discoloration for about thirty hours after I woke that looked like it, and definitely wasn't an effect of any potion or topical I'm familiar with." There's a note to this tone that, while not possessing a single shade of arrogance, means that if it is such an effect, the potion or topical must have been beyond exotic.
"You found some recognition," Severus notes calmly, pretending not to see the visitor's cold sweat and disturbed breathing because, if it were him, he'd want to shove them aside and get back to the facts asap.