He ended by believing that the teeth of the drowned man had planted an insect there which was devouring him.

The part of his neck where the scar appeared, seemed to him to no longer belong to his body; it was like foreign flesh that had been stuck in this place, a piece of poisoned meat that was rotting his own muscles.
In this manner, he carried the living and devouring recollection of his crime about with him everywhere.

When he beat Therese, she endeavoured to scratch the spot, and sometimes dug her nails into it making him howl with pain.

She generally pretended to sob, as soon as she caught sight of the bite, so as to make it more insufferable to Laurent.

All her revenge for his brutality, consisted in martyrising him in connection with this bite.
While shaving, he had frequently been tempted to give himself a gash in the neck, so as to make the marks of the teeth of the drowned man disappear.