Yellow looking crust after laser hair removal on face, should I be concerned? (photo)

Thank you for your question! This may represent a partial thickness burn which usually can be treated with local wound care. After only three days, this is unlikely to be infected as that usually occurs after 5-7 days. You should seek immediate consultation with a plastic surgeon who can evaulate and treat your condition. Her will also be able to advise you regarding changes in pigmentation due to burns from LASER hair removal. Best of luck!