Muwatta Malik:Hajj:Hadith 830
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ أَيُّوبَ بْنِ مُوسَى، أَنَّ عَبْدَ اللَّهِ بْنَ عُمَرَ، نَظَرَ فِي الْمِرْآةِ لِشَكْوٍ كَانَ بِعَيْنَيْهِ وَهُوَ مُحْرِمٌ ‏.‏

Yahya related to me from Malik from Ayyub ibn Musa that Abdullah ibn Umar once looked in the mirror for something that was irritating him while he was in ihram.