The Messenger of Allah ﷺ had himself cupped on the surface of his foot because of a pain in it while he was in the sacred state (wearing ihram). Abu Dawud said: I heard Ahmad say: "Ibn Abi 'Arubah narrated it in Mursal form". Meaning from Qatadah. (Using translation from Abū Dāʾūd 1837)  

«أَنَّ رَسُولَ اللهِ ﷺ احْتَجَمَ وَهُوَ مُحْرِمٌ عَلَى ظَهَرِ الْقَدَمِ مِنْ وَثْءٍ كَانَ بِهِ»  

[Machine] "The Prophet ﷺ was cupped on his head while he was in a state of ihram, seeking relief from a headache that he was experiencing."  

«أَنَّ النَّبِيَّ ﷺ احْتَجَمَ فِي رَأْسِهِ وَهُوَ مُحْرِمٌ مِنْ صُدَاعٍ كَانَ يَجِدْهُ»