i had tonsilitas the week before my op had antibiotics right up till the day before op didnt tell them though i also was coughing a lot n full of cold but they still did the op on pland day as my breathing was ok ! so long as its not effecting your breathing from your lungs it should not cause a problem with the op but as its a sore throat lemsips with honey or hot black current n orange drinks with honey added will help sooth it and it should go in couple of days any way 🙂