Sayyiduna Abdullah bin Unays al-Ansari (may Allah be pleased with him) relates that al-Mustanir bin Rizam the Jew struck me in the face with a stick of shawhat wood, splitting my head open, inflicting a wound that displaced the bone or one that reached the membrane of the brain. I brought this wound to the Messenger of Allah (peace and blessings be upon him); he (peace and blessings be upon him) uncovered it and spat on it, and after that it caused me no pain at all.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 13931