The narrator said: My paternal uncle told me that Abu Umamah was afflicted with an ailment which the people of Madinah call al-dhubh, so the Messenger of Allah (peace and blessings be upon him) said: "I will certainly make every effort for Abu Umamah, or: I will do all that can be excused." He said: So he (peace and blessings be upon him) cauterised him with his own hand, but he died. Thereupon the Messenger of Allah (peace and blessings be upon him) said: "An evil death for the Jews; they say: Why was it (the ailment) not removed from their companion? Yet I have no power over anything from Allah, neither for him nor for myself."
Hadith Referenceالمعجم الكبير للطبراني / باب الألف / 892