Sunan Abu Dawud
3859
Sahih+3

Narrated Abu Kabshah al-Ansari: The Messenger of Allah (ﷺ) used to have himself cupped on the top of his head and between his shoulders, and that he used to say: If anyone pours out any of his blood, he will not suffer if he applies no medical treatment for anything

SahihAl-Albani
SahihMuhammad Muhyi Al-Din Abdul Hamid