كتاب السلام
39  
The Book of Greetings
(20)
Chapter: Reciting Al-Mu'awwidhat As Ruqyah For The Sick, And Blowing Over Them
(20)
باب رُقْيَةِ الْمَرِيضِ بِالْمُعَوِّذَاتِ وَالنَّفْثِ ‏‏
Sahih Muslim 2192 b

'A'isha reported that when Allah's Messenger (ﷺ) fell ill, he recited over his body Mu'awwidhatan and blew over him and when his sickness was aggravated I used to recite over him and rub him with his band with the hope that it was more blessed.

حَدَّثَنَا يَحْيَى بْنُ يَحْيَى، قَالَ قَرَأْتُ عَلَى مَالِكٍ عَنِ ابْنِ شِهَابٍ، عَنْ عُرْوَةَ، عَنْ عَائِشَةَ، أَنَّ النَّبِيَّ صلى الله عليه وسلم كَانَ إِذَا اشْتَكَى يَقْرَأُ عَلَى نَفْسِهِ بِالْمُعَوِّذَاتِ وَيَنْفُثُ فَلَمَّا اشْتَدَّ وَجَعُهُ كُنْتُ أَقْرَأُ عَلَيْهِ وَأَمْسَحُ عَنْهُ بِيَدِهِ رَجَاءَ بَرَكَتِهَا ‏.‏
Reference : Sahih Muslim 2192b
In-book reference : Book 39, Hadith 69
USC-MSA web (English) reference : Book 26, Hadith 5440
  (deprecated numbering scheme)