digitalbusker quoted The Well of Ascension by Brandon Sanderson (Mistborn, #2)
Content warning Spoilers for Mistborn: The Alloy of Law
As Marsh slumped to the ground, Sazed could see that he'd driven one of the eye-spikes back into the front of the skull, crushing the bone around the socket.
— The Well of Ascension by Brandon Sanderson (Mistborn, #2) (94%)
The fact that in the next three hundred some years Marsh never heals that with fGold, even accidentally, makes me think there's something about Hemalurgic spikes that keeps them locked in place.