Twisting the knife in the wound is a powerful expression that suggests causing more pain to someone who is already hurt. There are a number of synonyms for this phrase that can be used depending on the context. Some examples include rubbing salt in the wound, pouring gasoline on the fire, kicking someone when they're down, digging the knife deeper, exacerbating the situation, and adding insult to injury. All of these phrases convey a similar sentiment of causing additional pain or frustration to someone who is already dealing with a difficult situation or challenge. It's always important to choose words carefully and be conscious of their potential impact on others.