He still carries around a knife.
It's nothing like the one he used to carry around (the one that cut the tips of his left pinky and ring-finger off clean, leaving them shorter than the others). It's small and red, and it fits into his pocket. It doesn't need a nearly-indestructible sheath, and has a couple of other uses (some of which include bottle-opening, nail-filing, and picking things) besides.
He doesn't use it, but he likes the weight of it. He likes the knowledge of what a knife on his person means. It's a memory, a feeling he tries to get back on those days when he's feeling particularly alone; or when he swears he can hear the wind whisper his name the same way Lyra might if she were trying to get his attention.
Sometimes, he'll just hold it with his left hand in his pocket, and remember things. It doesn't make all of it hurt any less, but it's better than nothing.