Prophet (SAW)'s Prayers When looking in the mirror

Recite:

اللَّهُمَّ أَنْتَ حَسَّنْتَ خَلْقِي فَحَسِّنْ خُلُقِي

"O Allah, just as You have made my external features beautiful, make my character beautiful as well". (Hisnul Hasin)