I am so sorry that I couldn’t attend your birthday party, I just have a lot of things going on and I’m trying to keep my family safe during this pandemic I hope you can understand my situation, although I wish you a happy # birthday, have a great day.
One way I would write a letter on why I couldn’t attend someone’s birthday
i apologize for my absence from your party. i couldn't show up because i wasn't finished with my 40 hours of violin practice. unfortunately, your party schedule badly collided with my practice time. obviously, i chose practice over celebrating your birthday. maybe next year i'll show up with a gift.
Junior describes himself as having an enormous skull and being so skinny that when he turned sideways he'd disappear. He is over exaggerating his features to get sympathy from the reader and to create humor. A hyperbole is an over exaggeration.