This morning I woke up and noticed a painful bump on the roof of my mouth. It's about 1/4 of an inch away from where my wisdom tooth was taken out two years ago. It's somewhat hard and seems to be less than the size of a pencil eraser. I don't know if I should be concerned seeing how it seems to have showed up over night. I do wear a retainer to bed, but it's just beyond the retainer and I've never had any issues with the retainer before (it's been several years).