It says on the link to use an oxygenating toothpaste and mouthwash. When you gargle, tilt your head back and gargle for at least 30 sec to 1 min(taking a break in between obviously). Do you have sinus problems? When I had mouth surgery once the doctor told me to use 10% hydrogen peroxide, the kind you use for cuts - 1 part hydrogen peroxide to 3 parts water and gargle. If your throat is this painful you should see a doctor today - there's also a numbing mouthwash they could give for the pain. Do you have a fever?