The Prophet ﷺ wiped his head with the leftover water that was on his hand.
أن النبي ﷺ مسح برأسه من فضل ماء كان في يده.
Abu Dawud narrated it (130) from Musaddad, who said, Abdullah bin Dawud narrated to us, from Sufyan bin Saeed, from Ibn Aqeel, from her. Its isnad is also hasan.Then Abu Dawud also narrated it (131), as did Ibn Majah (441), both of them from Waki, who said, Hasan bin Salih narrated to us, from Abdullah bin Muhammad bin Aqeel, from her, that the Prophet ﷺ would not perform wudu without inserting his two fingers into the hollows of his ears. This is also hasan.As for what Ibn Majah narrated (458) through Rawh bin Qasim, from Abdullah bin Muhammad bin Aqeel, from her, she said, "Ibn Abbas came to me and asked me about this hadith," meaning her hadith in which she mentioned that the Messenger of Allah ﷺ performed wudu and washed his feet. Ibn Abbas said, "The people insist on nothing but washing, yet I find nothing in the Book of Allah except wiping."Bayhaqi said (1/72), "If this is sahih, it is possible that Ibn Abbas held the view that the reading with the genitive case applies, and that it requires wiping. Then, when it reached him that the Prophet warned against neglecting to wash them, or neglecting part of them, he came to hold that washing them was obligatory, and he read it with the accusative case. We have narrated from him that he read it with the accusative case." End.