If your nose is constantly running it means that something is irritating or inflaming your nasal tissues.
When those nasal tissues become inflamed or irritated your nose will start to run.
You can try using a salt water rinse to rinse your nasal passages out to remove irritants that could be causing your nose to run constantly or take some antihistamines to stop the runny nose.
Another thing you can do to clear up a runny nose is to take a steamy shower and take some medicine that you sniff through your nose and stay hydrated by drinking plenty of fluids.