I remember in like 4th grade I stabbed myself in the leg with a pencil on accident and snapped a piece of the "lead" off in my leg. My brain spiraled for weeks thinking I had essentially poisoned myself and would be dying shortly. Finally told my parents, who said "okay lets go talk to the doctor" who, very sweetly, told me that little piece of graphite in my leg would cause essentially no harm. It's still there, a l…
Semi-permanent, actually; it faded after a couple decades. Probably wormed it's way into my brain. Sometimes I'm shocked I'm still alive.