Getting rid of a cut in my mouth?

So I had my tonsils out a couple years ago, and now I have a cut on the edge of where one used to be. When I wake up in the morning it is swollen and it hurts to swallow/drink. If I open my mouth to wide or eat something salty or my younger brushes up against it it starts to hurt A LOT. What's going on/ what's a good way to get rid of this cut fast? I've had it for a week or a little longer