Zit

google

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1960s: of unknown origin; apparently originally teenagers' slang in North American English.

wiktionary

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Uncertain origin, first attested as 1960s North American English slang. Compare English chit(“pimple, wart”), German Zitze(“teat, nipple”).

etymonline

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zit (n.)

"acne pimple," 1966, originally U.S. teenager slang, of unknown origin.