I didn't know that idiom in English, but from what I see, there are some expressions that can fit. They have slightly different meanings:

• Echar leña al fuego: do or say something to worsen a situation
• Echar sal en la herida: do or say something that increases somebody's pain (physical or emotional)
• Sacar los trapos sucios: make public someone else's faults
• Revolver la mierda: bring back an issue that is settled

I didn't know that idiom in English, but from what I see, there are some expressions that can fit. They have slightly different meanings:

• Echar leña al fuego: do or say something to worsen a situation
• Echar sal en la herida: do or say something that increases somebody's pain (physical or emotional)
• Sacar los trapos sucios: make public someone else's faults
• Revolver la mierda: bring back an issue that is settled