Do you give your Sim children plastic surgery if they don't look pretty enough for you?

Nope, never. Sometimes I don't even bother changing anything, including the clothes they grew up in! Now if something is glitched or the result of a bug or something, I wouldn't hesitate to fix that. Had to change a born in-game toddler's gender once - had 6 kids, all girls, changed the 6th to a boy to get my heir. Sure, could have kept going, but really?! Had enough lol.

When I change things, it's usually superficial stuff; hair/eyebrows, makeup, accessories, clothes, etc.