you have millons of hairs in your nose and all over your body to protect yourself and make sure your boogies dont just fall out but anyways when you inhale smoke through your mouth it burns of all the hairs in the back of your throat and that is how a doctor can tell you smoke, so in turn it does the same exact thing to your nose, not so pretty, although it may in turn give you an extra punch to your high since the smoke is going directly to your brain, it may not be something you want to do. i do blow my hit out through my nose occasionaly but i wouldnt make it a regular practice, oh and never try to blow/inhale smoke through your nose when you have a cold, its really not pretty.