I agree. Call you pedi, they will know better if anything needs to be treated. I was in the same boat this past week. This is the second time my LO was congested, but this time he started developing a cough. Took him to his pedi and it turns out he has a sinus infection. Poor guy :( But this weather sure does not help. He's been a bit stuffy this past month in general. I'm ready for spring!
Hope your LO feels better soon!