He watches her set sponge and gauze to wounds to clean, and no, it's not comfortable, but he'll save any biting for when the needle is pulling through his skin. At first he is still, jaw tight in steely toleration, and then the cleaning chemical finds his wounds, and he jolts once in automatic flinch back. What on earth--?

"That feels like poison," is lazy accusation, more complaint than anything else. If he thought it was, he'd probably be out the door with his ruined clothing in hand. As it stands, he's willing to humour the Muggle.

She did warn him.