When a white bump appears on the inside of the lip, most of these oral lesions are common and ultimately harmless. The white appearance often results from the buildup of keratin, a protective protein, or from a collection of fluid or inflammatory cells beneath the mouth’s lining. Identifying the bump’s characteristics—such as its duration, pain level, and texture—can help determine its likely cause and whether a dental evaluation is necessary.
Common Causes of Acute White Bumps
The most frequent causes of a white bump are acute, temporary conditions that resolve on their own. The common aphthous ulcer, often called a canker sore, is a non-contagious lesion affecting the soft tissues inside the mouth. It typically presents as a round or oval ulcer with a distinct white or yellowish-gray center surrounded by a bright red border. These sores can be quite painful, especially when speaking or eating, and usually heal naturally within 7 to 14 days without leaving a scar.
Another common acute cause is trauma or irritation to the lip lining. This happens after accidentally biting the lip, rubbing against a sharp tooth edge, or being scraped by ill-fitting dental work. When the soft tissue is injured, the body reacts by producing a layer of keratin, which gives the wound a temporary white appearance. This type of localized injury typically heals quickly once the source of the irritation is removed, often within a few days to a week.
Persistent But Usually Benign Lesions
Some white bumps are persistent because they represent an anatomical variation or a longer-lasting physical response. Mucoceles are soft, dome-shaped swellings that form when a minor salivary gland duct is damaged or blocked, causing mucus to leak and collect beneath the surface. They are most common on the inner lower lip and may look clear, sometimes with a bluish tint, or white if the tissue is thickened. Mucoceles are typically painless and often rupture and heal on their own within three to six weeks, though they can recur.
Fordyce spots are visible sebaceous (oil) glands that occur in areas without hair follicles, such as the lip lining. These small, slightly raised spots are generally yellow-white or skin-colored, measuring 1 to 3 millimeters in diameter, and can appear individually or in clusters. They are completely harmless, not contagious, and require no treatment, as they are present in a large percentage of adults.
A different kind of white patch, frictional hyperkeratosis, occurs when chronic, low-level irritation causes the oral mucosa to thicken, much like a callus on the skin. This condition often results from behaviors like chronic lip chewing, or from constant rubbing against rough dental surfaces or appliances. The patch is usually non-painful, white, and slightly rough, and it will resolve once the source of friction is identified and eliminated.
Warning Signs and When to See a Dentist
While most oral bumps are benign, certain characteristics should prompt a professional evaluation. The most significant red flag is duration; any white lesion that persists for longer than two to three weeks without healing requires immediate attention. Lesions that rapidly increase in size, develop a firm or hard texture, or are accompanied by numbness, difficulty swallowing, or a persistent sore throat are also concerning signs.
It is important to look for changes in color or texture, such as a white patch mixed with red areas (speckled leukoplakia). This may signal a higher possibility of serious tissue changes. Leukoplakia is a persistent white or gray patch that cannot be scraped away and is considered a potentially precancerous lesion, though most cases are not cancerous. Any lesion that does not have a clear, benign cause, or one that is painful and does not improve within two weeks, should be examined promptly.