Learn Hardcore Chinese: tuìshāo yǐhòu, tā juéde shēntǐ hǎo le yìdiǎnr, xīnqíng yě qīngsōng duō le. - After her fever went down, she felt a bit better physically, and her mood also became much more relaxed.

退烧tuìshāo　以后yǐhòu，　她tā　觉得juéde　身体shēntǐ　好hǎo　了le　一点儿yìdiǎnr，　心情xīnqíng　也yě　轻松qīngsōng　多duō　了le。tuìshāo yǐhòu, tā juéde shēntǐ hǎo le yìdiǎnr, xīnqíng yě qīngsōng duō le.

After her fever went down, she felt a bit better physically, and her mood also became much more relaxed.

Breakdown of tuìshāo yǐhòu, tā juéde shēntǐ hǎo le yìdiǎnr, xīnqíng yě qīngsōng duō le.

change-of-state particle

Questions & Answers about tuìshāo yǐhòu, tā juéde shēntǐ hǎo le yìdiǎnr, xīnqíng yě qīngsōng duō le.

Why does 退烧 mean to have one's fever go down? Is 退 literally to retreat here?

Yes, 退 originally has the idea of to move back / recede / subside. In 退烧, it means the fever goes down or subsides.

So 退烧 is a very natural Chinese way to say:

the fever went down
to recover from a fever
to no longer have a fever

It does not mean someone is physically stepping backward. In medical or everyday health contexts, 退 is often used for symptoms decreasing, like something receding.

Why is 以后 used after 退烧? Does 退烧以后 mean after the fever went down or after recovering from the fever?

以后 means after. It comes after the event it refers to, so:

退烧以后 = after the fever went down

This is a very common Chinese pattern:

吃饭以后 = after eating
下课以后 = after class ends
回家以后 = after going home

So the structure is:

[event] + 以后

In this sentence, 退烧以后 sets the time frame for what follows.

Could this also be said with 退烧后 instead of 退烧以后?