Blowing the nose too hard causes headache because blowing the nose too hard and the patient is in a breath-holding state can lead to an increase in intracranial pressure and cause headache and other symptoms. If the patient has a lot of nasal mucus and a pus nose, it is considered to be acute or chronic purulent sinusitis caused by bacterial infection. Inflammation in the sinuses causes mucosal swelling, pus pressure on nerves and stimulation of nerve endings by bacteria and toxins, which can also cause headache, and headache is one of the common symptoms of sinusitis. If the patient has acute or chronic rhinitis or sinusitis, blowing the nose should not be done with force, especially not by pressing both nostrils, otherwise it will not only fail to blow the nose out, but will instead pass through the eustachian tube located on both sides of the nasopharynx and enter the middle ear tympanic cavity, causing acute purulent otitis media to occur.