Reference: Fataawa al-Hajj wal-‘Umrah waz-Ziyaarah – Page 58
Question: I have a habit of playing with my hair when I am thinking. After I had entered the state of ihraam, I forgetfully did this and some hair fell out. Do I have to make an expiation?
Response: There is nothing required of you due to that which Allaah سبحانه و تعالى mentions regarding the believers that they said:
{Our Lord! Punish us not if we forget or fall into error…}, [Soorah al-Baqarah, Aayah 286].
And Allaah has responded to their request as it has been mentioned on the authority of the Messenger of Allaah ﷺ that Allaah سبحانه و تعالى said:
«I have done [this]». Narrated by Imaam Muslim in his Saheeh.
