I feel a small lump in the top part of my lower lip. I can only feel it if I press in hard with my tongue or fingers. I've felt it for two months. It seems like the size hasn't changed. I don't think it's a minor salivary gland because it's above where the others are located. I have a dentist appointment at the end of this week. Any idea what it could be? I'm worried that it could be oral cancer.