Nope. Itachis lines are not to show stress, because in the manga, when his mother was carriying him when he was a baby, she had those same lines as itachi, so he got them of his mother(Just makes us wonder why his mother has them). And Iruka did have that scar as a little kid, im almost 100 percent sure he wasnt born with that scar, he probably got it training as a little boy. And Naruto, before nine tails was sealed inside of him, he didnt have those lines on his cheeks, he got them from nine tails, when they sealed him inside of naruto
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Where are sasuke's mom's lines?
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And Naruto had the lines when he was born, it was from being surrounded with nine tails chakra for so long. It altered his appearance, giving him the whiskers. He had them before the nine tails was sealed inside him.