Sahih al-Bukhari 4206
Narrated Yazid bin Abi Ubaid:
I saw the trace of a wound in Salama's leg. I said to him, "O Abu Muslim! What is this wound?" He 
said, "This was inflicted on me on the day of Khaibar and the people said, 'Salama has been wounded.' 
Then I went to the Prophet (ﷺ) and he puffed his saliva in it (i.e. the wound) thrice., and since then I have 
not had any pain in it till this hour."
حَدَّثَنَا الْمَكِّيُّ بْنُ إِبْرَاهِيمَ، حَدَّثَنَا يَزِيدُ بْنُ أَبِي عُبَيْدٍ، قَالَ رَأَيْتُ أَثَرَ ضَرْبَةٍ فِي سَاقِ سَلَمَةَ، فَقُلْتُ يَا أَبَا مُسْلِمٍ، مَا هَذِهِ الضَّرْبَةُ قَالَ هَذِهِ ضَرْبَةٌ أَصَابَتْنِي يَوْمَ خَيْبَرَ، فَقَالَ النَّاسُ أُصِيبَ سَلَمَةُ‏.‏ فَأَتَيْتُ النَّبِيَّ صلى الله عليه وسلم فَنَفَثَ فِيهِ ثَلاَثَ نَفَثَاتٍ، فَمَا اشْتَكَيْتُهَا حَتَّى السَّاعَةِ‏.‏