Mucous extravasation phenomenon is a swelling of connective tissue consisting of a collection of fluid called mucus.

This occurs because of a ruptured salivary gland duct usually caused by local trauma (damage) in the case of mucous extravasation phenomenon and an obstructed or ruptured salivary duct in the case of a mucus retention cyst.

[3] The size of oral mucoceles vary from 1 mm to several centimeters and they usually are slightly transparent with a blue tinge.

Their duration lasts from days to years,[4] and may have recurrent swelling with occasional rupturing of its contents.

It can also be found on the inner side of the cheek (known as the buccal mucosa), on the anterior ventral tongue, and the floor of the mouth.

Other causes of bumps inside lips are aphthous ulcer, lipoma, benign tumors of salivary glands, submucous abscesses, and haemangiomas.

These include laser and minimally invasive techniques, which means recovery times are reduced drastically.