slide 2 of 12. Skin The skin is the largest organ in the human body. Its main job is to maintain the body's temperature, which means that sweat is created to cool the body, and goosebumps or raised hair occur to trap heat in the body. Along with sweat glands, the skin contains oil glands.
...However, if I am wrong about that, the answer is that acetaminophen (and its metabolites) are identifiable for up to 48 hours after you took the pill. Less if you took tiny doses, but up to standard clinical doses (<8g), it's 48ish hours.
Acetaminophen can be toxic to dogs and cats, but cats are 7 to 10 times more susceptible to acetaminophen toxicity than dogs are. Once swallowed, acetaminophen reaches the blood stream within 30 minutes; toxic effects are rapid and damage the liver and red blood cells.