Mishkat al-Masabih 4561
Ash-Shifa’ daughter of ‘Abdallah told that when she was with Hafsa God’s messenger entered and said:
“Why do you not teach this one the spell for skin eruptions as you taught her writing?” 

Abu Dawud transmitted it.
وَعَن الشَّفاءِ بنت عبد الله قَالَتْ: دَخَلَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ وَأَنَا عِنْدَ حَفْصَةَ فَقَالَ: «أَلَا تُعَلِّمِينَ هَذِهِ رُقْيَةَ النَّمْلَةِ كَمَا عَلَّمْتِيهَا الْكِتَابَةَ؟» . رَوَاهُ أَبُو دَاوُد