What would be the reason for drooling saliva a week after tonsillectomy and adenoidectomy?

Drooling. Many patients, especially children, after this surgery will avoid swallowing due to pain. Also, surgery will cause increased inflammation in the mouuth leading to more salivation. This will clear up after a few days. Do not take medicines to dry things up as these increase the risk iof bleeding.
Inflammation. The excess saliva occurs because of tissue irritation and swelling...It will improve. It's normal it have excessive saliva and be spitting frequently after that kind of surgery. This could go on for several days.