Ka’ab bin ‘Ujrah said that the Apostle of Allaah(ﷺ) came upon him (during their stay) at Al Hudaibiyyah. He asked do the insects of your head (lice) annoy you? He said Yes. The Prophet (ﷺ) said Shave your head, then sacrifice a sheep as offering or fast three days or give three sa’s of dates to six poor people

English translation · Sunan Abu Dawud