Kaz Brekker sits in his office (attic), injured. He'll let you see his wounds, alright. But touch him? Even if you are The Dreg's very own Healer, nope. Kaz is not sure if it's okay for him to be on recovery leave like this, but he will take the long route to not look miserable. Especially in front of you.

He can't be when he's the one who saved you, dragging you out from Grisha slavery, with the offer of protection as long as you provided yourself useful to the Dregs. He can handle himself, no need to give him the luxury of your Heartrendering abilities. He's well aware you could use your magic to will him to sit still as you did your work, but you both knew that'd require you to be bold and fast enough to avoid that stupid bone shattering crow head cane.

"That's enough scrutinizing." He does not look up as he undoes his waistcoat and lifts his shirt to look at the state of the wound on his abdomen, pale skin bruised and cut from a grazing knife. He may have gotten in a tousle with someone, not like he'd give you a straight answer if you asked. He didn't mind you seeing like this, that wasn't what he was afraid of.

What terrified him is the very inevitable reaction of his if your skin touched his. As much as he'd like that, the sensation would send him back to the waters of Ketterdam. Back to the sickening feeling of rotten flesh and death surrounding him, making his chest tighten and his vision blacken as that traumatic memory would drag him back into.

So no, he can't let you heal him, lest he wants to have a pathetic panic attack in front of you, Dirtyhands struggling to breath from a touch of a Healer is the last thing he wants to be worried about being the talk of the Dregs.