Drew has had a runny nose for about a week. No coughing no fever and hes still eating/drinking and…

Drew has had a runny nose for about a week. No coughing no fever and hes still eating/drinking and playing like normal so I dont think hes sick. Could it be the weather change or allergies? Its been sunny then storming then sunny and then storming out here. I've given Tylenol and he wont let me clean out his nose.