(80) باب الْمِجَنِّ وَمَنْ يَتَتَرَّسُ بِتُرْسِ صَاحِبِهِ
Narrated Sahl:
When the helmet of the Prophet (ﷺ) was smashed on his head and blood covered his face and one of his front teeth got broken, `Ali brought the water in his shield and Fatima the Prophet's daughter) washed him. But when she saw that the bleeding increased more by the water, she took a mat, burnt it, and placed the ashes on the wound of the Prophet (ﷺ) and so the blood stopped oozing out.
Reference: Sahih al-Bukhari 2903
In-book reference: Book 56, Hadith 117
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 4, Book 52, Hadith 152