Name of teacher
Respected Sir/ ma'am,
I request you to kindly excuse me for not taking the haircut, as per your direction yesterday. Though I wished to obey you with all my heart, we were all engaged the whole evening , with the unfortunate incident of my grandfather being hospitalized, hence was unable to go to take a haircut.
I assure you that I will follow your direction as soon as possible and apologize whole heartedly for the delay.