صَحِيحُ مُسْلِمٍ
Sahih Muslim 1201 f
The Book of Pilgrimage
It is permissible for a Muhrim to shave his head if there is a problem, but it is obligatory to offer a Fidyah for shaving it, and Clarifying what the Fidyah is
وَحَدَّثَنَا يَحْيَى بْنُ يَحْيَى، أَخْبَرَنَا خَالِدُ بْنُ عَبْدِ اللَّهِ، عَنْ خَالِدٍ، عَنْ أَبِي قِلاَبَةَ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ أَبِي لَيْلَى، عَنْ كَعْبِ بْنِ عُجْرَةَ، رضى الله عنه أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم مَرَّ بِهِ زَمَنَ الْحُدَيْبِيَةِ فَقَالَ لَهُ " آذَاكَ هَوَامُّ رَأْسِكَ " . قَالَ نَعَمْ . فَقَالَ لَهُ النَّبِيُّ صلى الله عليه وسلم " احْلِقْ رَأْسَكَ ثُمَّ اذْبَحْ شَاةً نُسُكًا أَوْ صُمْ ثَلاَثَةَ أَيَّامٍ أَوْ أَطْعِمْ ثَلاَثَةَ آصُعٍ مِنْ تَمْرٍ عَلَى سِتَّةِ مَسَاكِينَ " .
Ka'b b. Ujra (Allah be pleased with him) reported that the Messenger of Allah (ﷺ) happened to pass by him during the period of Hudaibiya. Thereupon he (the Prophet) said to him (Ka'b b. Ujra): Do these vermins trouble your head? He said: Yes. Thereupon he (the Prophet) said: Shave your head. Then sacrifice a goat or observe fasts for three days or give three sits of dates to feed six needy persons.
Sahih Muslim, 1201 fSahihصحيح