What happens if you blow into a baby's nose is it harmful?

Yes, put you mouth over your baby's mouth and then blow gently. You will probably only have to blow once and wipe the mucus from his nose! This really worked for my son who is a week shy of turning 4 months. He got the cold for the first time and was so congested that he could not eat. The mucus remover seems to irritate his nose with so many tries to remove the snot. One blow cleared his nose, he ate and now is sleeping peacefully. Hope this helps! Again don't blow too hard!