Here is the story. Coughing should be avoided but some might happen. You have a 7 day supply of cough medicine so use it if you need it. I didn't need it but you be the judge. Next, ice water with a straw in it. When you feel the urge to cough, take a sip and warm it for a few second in your mouth before swallowing. The water needs to be cold but not ice water cold. Sip often to avoided getting to the point where you need to cough. You will run to the bathroom often getting rid of the water. If you feel the need to cough, lean forward and with you vocal cords open, breath out fast. It's not as good as a cough but it often will clear the mucus accumulation. Avoid dairy and chocolate because they tend to make it worst.
Coughs aren't good but the surgery can withstand some misuse. Coughing fits are bad and should be avoided. I don't know if Dr Haben told you this but he has never had a VFS come undone.