It is narrated from Sayyiduna Ka'b bin 'Ujrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) ordered me (when lice caused me distress) to shave my head, then to fast for three days or feed six needy people, because he (peace be upon him) knew that I did not have a sacrificial animal to offer as ransom.
Hadith Referenceالسنن المأثورة / باب ما جاء في فدية الأذى / 444
Hadith Takhrijسنن ابن ماجہ، المناسک، باب فدیہ المحصر، رقم: 3080 وقال الالبانی: حسن