Puppy congested nose.. help me please?

So I got a 4 month old beagle mix shar pei puppy and about 3 days ago he started sneezing a lot first the discharge was clear, now I noticed when he's sleeping he sounds congested and when I just cleaned his nose the discharge was yellow. I took him to the vet 2 days ago and they said he was ok and gave me antibiotics for the dog but im still concerned.... what can I do to relieve it for at least tonight.. tomorrow morning I will take him back to the vet and see what's up.