Metal Mouth Message Board

Here is a picture, it feels bigger than it looks.

Hi I have a hard lump on my gum about 1cm round and a sticks out a couple of mm. Im wondering what it is. I have had braces for 2 years and noone has mentioned it, Im pretty sure it has been there for a long time but it seems larger than before. My next appt is 19 dec. Just wondering what it could b...