Hello, my son has a runny nose, sometimes it gets congested. What can …

Hello, my son has a runny nose, sometimes it gets congested. What can I do? I rinse with a saline solution and suction it out with an aspirator. I'm giving him Nazivin drops. I don't know if it's because of his teeth or not, I feel like he has a lower one and a upper two coming up, but they haven't come up yet? Do you think it's because of his teeth or infection? There is no fever.