The Messenger of Allah ﷺ spat on the leg of Amr bin Muaz when it had been severed, and it healed.
إن رسول الله ﷺ تفل في رجل عمرو بن معاذ حين قطعت رجله فبرا.
No references are available.
Ibn Hibban (6509) and Abu Naeem in Marifat Sahabah (4/2036) both narrated it through Husayn bin Hurayth Abu Ammar, who said, Ali bin Husayn bin Waqid narrated to us, my father narrated to me, Abdullah bin Burayda narrated to me, who said, I heard my father Burayda say, and then he mentioned it.Its chain of transmission is hasan because of Ali bin Husayn bin Waqid and his father, for both of them are hasan in narrating hadith.