Musnad Ahmad 374:1

Hassan ibn Musa narrated to us, he said: Zuhair narrated to us, from Abu al-Zubayr, from ‘Amr ibn Shu‘ayb, from his father, from one of the companions of the Prophet, may Allah bless him and grant him peace, who said: The Messenger of Allah, may Allah bless him and grant him peace, cauterized Sa‘d, or As‘ad ibn Zurarah, in his throat for the *dhibhah* (quinsy/throat inflammation). And he said: "I will not leave any distress in my soul regarding Sa‘d or As‘ad ibn Zurarah."