20 month old with bad cough??

My son has a bad cough he is losing a lot of sleep. He coughs so hard he throws up sometimes. I gave him a prescription cough syrup he got last winter and it helped a little. One of the other kids at daycare had bronchitis. Should I take him in or just wait it out?? He doesn't have a runny nose or anything. He had a low grade fever lastnight 100.4 under the arm. He just has a nasty cough. It is pretty "wet" sounding.