Newborn has a cold…

My 4 week old has become very sniffly and has a nasty wet cough. He doesn’t have a fever at the moment and I’ve seen the guidance of using humidifiers and saline drops but wondered if anyone had any other hacks to help us get through the next few days…

Is it worth letting a doctor know or should I see how it goes? FTM here so I’m not sure what is Over the top