我知道你的考试成绩比我好——没必要一再提这事来让我难堪。

I know your exam results were better than mine - there's no need to ___rub ___it ___in.

我不是故意要揭你伤疤，但你确实承诺过会自己处理这件事的。

I don't mean to ___rub ___it ___in, but you did promise you would handle this yourself.

别再提我犯的那个错了——你现在真是在往我伤口上撒盐。

Stop reminding me about that mistake I made - you're really ___rubbing ___it ___in now.