i have a small white bump on the roof of my mouth. It has grown a little in the past month or so. I noticed it about a month and a half ago. It doesn't hurt and it feels kind of soft, I can move it around a little bit with my finger. but it isn't going away. ?What could this be? I showed it to my dentist last month and he didn't sound too concerned about it. He just said watch and see if it grows.