Hi Shannon,
First, try to relax! Sometimes our kids to get the common cold and yes, they do get rid of it on their own. Trust your instinct tomorrow. If his cough has increased in sound or frequency, call your clinic. If you are still only hearing a dry cough every couple of hours, and you already know he's fighting a viral infection, I'd wait it out a few more days before calling. But definitely call if symptoms worsen before then!
Unfortunately, that's part of the guessing game with this disease..When do I call the doctor?...Is this something I should be concerned about?...We have all been there. Try to remember that there is really no question you can't ask your clinic. They have heard them all and they are prepared to answer them all! And...they have dealt with every one of us on this board as new moms trying to figure out this crazy disease! Good luck and I hope everyone in your home can get a good night's sleep tonight.