My baby was at the doc 2 days ago for a cough and runny nose, he prescribed cough syrup and antibiotics, but now my baby keeps crying and has a rash?

It happens: The rash may be from the illness or a reaction to one of the medicines. The cough med can make baby irritable & does little. The antibiotic might be needed if there really is a bacterial infection but most of these are viral, the antibiotic may trigger an allergic rash. Your choices are difficult. Either continue,stop all meds & see what happens, or go back to the doc.