I am not quite sure how long this has been present, but 2 weeks ago I noticed 2 different "spots" on the roof of my mouth, both which are no bigger than half the size of a penny, and both feeling slightly raised and rigid when i feel it with my tongue or finger (the rest of the roof of the mouth is smooth). These rigid spots are located toward the back of the roof of my mouth, almost where the palate turns from "hard" to "soft." Is this anything to be worried about or is this a natural texture of the roof of the mouth? Thank you so very much. Phil