Hello, you haven t given enough information for a complete answer. A description of your problem and perhaps a diagnosis could have helped a lot. I suppose you had sinusitis or another upper respiratory infection. Bacterial sinusitis that won t respond to treatment after 3 days needs another regimen. Viral infection of the sinuses or the rest of the upper respiratory tract won t respond to antibiotics anyway because viruses cannot be killed by them. Please take into account that most upper respiratory tract infections are indeed viral. So in conclusion, if you have no improvement after 3 days of treatment then you should contact your doctor. Another approach may have to be tried. Kind Regards!