You could also accidentally rub infected snot into your eye
and get an eye
infection, if you are careless.
The physiology of your head may be different from my head and you could experience a problem that I would not have, so it’s another risk you must assume.
This technique will work for almost any infection of the nose, if you‘re willing to take the risk. If an unfortunate side effect should happen to you, well, I am sorry.