My niece has a small blister like lesion to her bottom lip. It is red pearly in appearance about 2 mm in diameter. She is 6 years old and her father tells me it has been there for over a year. She denies any pain or irritation to the area, no systemic complaints other than occasional abdominal pain recently diagnosed with constipation dominant IBS . My niece tells me it does not bother her. Is this something we should be concerned about what do you think are some possible causes? Thanks