Bukhari 2903

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