A man from the Ansar said on the authority of Ka'b ibn Ujrah that he was feeling pain in his head (due to lice); so he shaved his head. The Prophet (ﷺ) ordered him to sacrifice a cow as offering.
Sunan Abi Dawud Book 11, Hadith 139
← Previous Hadith The Messenger of Allah (ﷺ) came upon him (during their stay) at al-Hudaybiyyah. He then narrated the rest of the tradition. This version adds: "He asked: Do you have a sacrificial animal? He replied: No. He then said: Fast three days or give three sa's of dates to six poor people, giving one sa' to every two persons."

Sunan Abi Dawud Book 11, Hadith 138 Next Hadith → Ka’b bin ‘Ujrah said I had lice in my head when I accompanied the Apostle of Allaah(ﷺ) in the year of Al Hudaibiyyah so much so that I feared about my eyesight. So Allaah, the exalted revealed these verses about me. “And whoever among you is sick or hath an aliment of the head.” The Apostle of Allaah(ﷺ) called me and said “Shave your head and fast three days or give a faraq of raisins to six poor men or sacrifice a goat. So, I shaved my head and sacrificed.

Sunan Abi Dawud Book 11, Hadith 140