Exercise and Sex after rhinoplasty. Does the increased blood flow somehow cause asymmetry or longer term issues with healing?

Thank you for your question.You are correct, that it is largely the bleeding and injury risks that are more concerning.  If you get your heart rate and blood pressure up early after surgery, and this causes bleeding into the tissues (a hematoma) you may get abnormal healing and scarring that would contribute to long-lasting asymmetry.Best to hold off on exercise and other activities before your surgeon feels it's safe to resume them.

Thank you for the question! Like most surgeons, I would advise you to wait about 3 weeks before engaging in strenuous physical activities after rhinoplasty. Even if sexual activity poses no risk of nasal trauma, it might elevate your blood pressure and increase your heartbeat. This might exacerbate your swelling and even increase a chance of bleeding. 
 An in-person exam with a board-certified plastic surgeon would be the best way to assess your needs and obtain expert medical advice. Best of luck!