From Sahih Bukhari (Hadith 5665):
Narrated Ka`b bin 'Ujara:The Prophet (ﷺ) passed by me while I was kindling a fire under a (cooking) pot. He said, "Do the lice of your head trouble you?" I said, "Yes." So he called a barber to shave my head and ordered me to make expiation for that
Reference: Bukhari 5665