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](http://lema.rae.es/drae/?val=le%C3%B1a)**: 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](http://lema.rae.es/drae/?val=trapo)**: make public someone else's faults
 - **Revolver la mierda**: bring back an issue that is settled