Oral cancer worries : Whiteness and other weird sore in area behind back lower teeth

Hey guys, recently I have been having allergies or been sick with something so I routinely just checked my throat. But what I saw while I was doing it was something a bit worrisome.

I can't name the area it's in but it's that area behind the lower back teeth where it's like an indent behind your teeth? I cant describe where it is but on both sides I have whiteness. And this weird looking blister thing. The blister thing has been there for a bit as well so I'm worried about that as well. But what about the white stuff near it? I have no idea what it is and where it is it's hard to describe but does anyone else have a similar problem? :(