In layman's terms, when a fever breaks, the fever has done its job. When you saturate your blankets with sweat, the fever is done, the infection is gone. You get chills because your body temp goes over normal, so you feel cold. So you bundle up. I mean that's what you do when you're cold, right? Bundling up raises your temperature, and that makes the infection die off.

However, this is only useful if you have an adult monitoring you while you doze and recover. Just willy-nilly heating yourself up while sleeping is a recipe for disaster after a certain age, and / or with certain infections.

get over a cold or the crud? blankets. Get over the flu? well that takes some doing. that's why the flu is such a huge deal. Kids get sick a lot, because their bodies are always experiencing new pathogens. but the flu is dangerous as fffffffffff. You can't just kill off a virus by making the environment warmer. That's why you have to take temperatures often and be vigilant.

but 80% of the time, sweating the cold away works. Parents know this because they rarely had the flu, and other parents talk about their snot-nosed children all the time. Snot nose = fluids, love, warmth. Anything else is a doctor visit. Sure, doctor can't do anything about the flu except diagnose it, but it's good to know if you should be prepped for an ER/hospital visit because anti-pyretics don't work.