I keep reading that at least in the case of viruses humidifiers and warmer air can kill viruses, especially if you have sinusitis. I was thinking that if you wear a mask you would achieve both higher humidity and the warmer air. Could this be a good alternative or supplement to nasal vaporizers/inhalers? You don't generally use inhalers all day, but you could wear a mask almost all day.
No, wearing a mask cannot help fight infection when sick.
A sick person can wear a face mask when around others only to help prevent the spread of flu. Wearing a face mask limits the spread of tiny infected drops that are released when a person talks, coughs or sneezes.
After all, the masks were originally designed to protect patients from the coughs and sneezes of a surgeon and not to help fight an infection.