Mr. Monk and the Man Who Shot Santa - S6-E10
Plot hole: This episode's entire story line takes place in the six days before Christmas (Dec. 19-24). "Bad Santa" is shot in the right shoulder on the 19th, sustaining a wound serious enough to require wearing a sling for the next several days. Yet at the end, a mere few days later, he's recovered enough to have a knock-down-drag-out fistfight with Monk, wielding a knife and throwing powerhouse punches with his wounded arm as though no injury had ever occurred. (00:38:00)
Answer: Notice also that in the opening credits scene when he is touching parking meters her also wipes his hand on his clothes each time he does it.