I've had a small round blister looking bubble right in the middle of my lower lip for a long time....probly like a yr maybe, it keeps coming back! It seems to grow, but not too big bout the size of....idk the pupil of an eye when it's not dilated or maybe the size of this letter "o". I can see it in the mirror, it looks white like a pimple n it gets hard sometimes. I unfortunately pop it because it is annoying n it's on my lip not in my mouth..... Clear stuff comes out n when it pops I hear it pop. I dnt know what it is but I wish it would go away :(