hi! thank for posting your query.... many a times, acute upper respiratory tract infections are viral in origin, which usually don t require any antibiotic treatment. as you have been already taken full course of amoxicillin , there is no further need to continue this medicine . As your cough is still persisting, you can continue cough suppressant for few more days and simultaneously get an x ray chest done and physician opinion for chest examination findings if any. If cough is associated with sputum formation, there are chances of lower respiratory involvement... Hope you have satisfied with the answer. If you have any further queries do not hesitate to ask. Wish you better health.