It was narrated that 'Aishah said: "Usamah stumbled at the threshold of the door and cut his face. The Messenger of Allah (ﷺ) said: 'Remove the harm (the blood) from him,' but I was repulsed by that. He started to suck the blood and remove it from his face, then he said: 'If Usamah were a girl, I would have adorned him and dressed him until I married him off."'
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا شَرِيكٌ، عَنِ الْعَبَّاسِ بْنِ ذَرِيحٍ، عَنِ الْبَهِيِّ، عَنْ عَائِشَةَ، قَالَتْ عَثَرَ أُسَامَةُ بِعَتَبَةِ الْبَابِ فَشُجَّ فِي وَجْهِهِ فَقَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " أَمِيطِي عَنْهُ الأَذَى " . فَتَقَذَّرْتُهُ فَجَعَلَ يَمَصُّ عَنْهُ الدَّمَ وَيَمُجُّهُ عَنْ وَجْهِهِ ثُمَّ قَالَ " لَوْ كَانَ أُسَامَةُ جَارِيَةً لَحَلَّيْتُهُ وَكَسَوْتُهُ حَتَّى أُنَفِّقَهُ " .
sunnah.com