Red, swollen area in mouth

On the left side of my mouth there's a painful area that is swollen and discolored, its like red and a little yellowish. It goes onto part of my cheek. I have a tooth that is about to be pulled in a couple days since it has so much decay, could it be because of the tooth? But it goes from my cheek, to the tooth, and then to where my tonsil would be. The area where my tonsils were are both discolored. The circled area is basically where it is. What could it be 😢