The blood will swiftly start to congeal into an ooze that's purple and brown, and skin in the local area becoming stiffer over the next couple minutes. Soon, the upper layers of flesh in that spot on his cheek will have turned to stone. It won't spread from there, but it will leave an uncomfortable chunk of immovable rock stuck to his cheekbone.

Sans steps back, sheathing his sword.

"You've got something on your face," he says. "You should go get that looked at."