For a couple of days, have been drinking ginger tea because I have scratchy throat but noticed that my upper gums are mildly swollen. Is it due to the tea because its soothes the scratchy or something else?

Ginger is very beneficial in many ways, but everyone's physiology is different. Like the old saying "what is good for the goose is not necessarily good for the gander". So I would have to say stop drinking the ginger tea for a couple of days and see if swelling goes away. If it goes away you will know why, otherwise, make an appt. with your dentist!