Hello, Welcome to HCM, As you are a known case of lung cancer, if you are having bleeding from the nose while blowing you need to consult your doctor at the earliest. Cause for the bleeding should be found out by physical examination and examination of the upper respiratory tract. You should be evaluated completely and the root cause for bleeding from the nose should be found out and appropriate treatment should be taken. I would suggest you to consult your ENT surgeon at the earliest for complete evaluation. Thank you.