Undecided Question

What is in my pit bulls mouth?

I have a two year old pit bull who has been healthy in every way. He's had all his shots and is very well taken care of. However, my boyfriend just noticed he has some kind of ball of skin on the inside of his mouth with little pimples scattered around it. Anyone know what this may be? I have a good picture of it, but I don't know how to upload it on here. I can email it if you want to see it. Thanks.