Mucous cysts develop when salivary glands become plugged. They’re usually temporary, but if left untreated, they can become permanent.

A mucous cyst, also known as a mucocele, is a fluid-filled swelling that occurs on the lip or the mouth.

The cyst develops when the mouth’s salivary glands become plugged with mucus. Most cysts are on the lower lip, but they can occur anywhere inside your mouth. They’re usually temporary and painless.

Mucous cysts are most commonly caused by trauma to the oral cavity, such as:

Inadequate dental hygiene can also put you at higher risk for developing mucous cysts. Some people develop these cysts as a bad reaction to tartar-control toothpaste.

Mucous cysts are most common in adolescents. However, these cysts can occur in people of all ages.

The symptoms of a mucous cyst vary depending on how deep the cyst lies within the skin and how often it occurs. Most cysts are not painful, but they can be uncomfortable. Frequent cysts can become painful over time.

Symptoms of cysts near the surface of the skin include:

  • raised swelling
  • bluish color
  • softness
  • lesions less than 1 centimeter in diameter

Symptoms of cysts deeper within the skin include:

  • rounded shape
  • whitish color
  • tenderness

Healthcare professionals rely on clinical symptoms for diagnosis. They may also ask if you have a history of trauma associated with lip biting. Your answer will help your healthcare professional make an accurate diagnosis.

In certain cases, a biopsy may be needed to make a diagnosis. Doctors may require a biopsy in cases where:

  • The mucous cyst is larger than 2 centimeters
  • The cyst’s appearance suggests adenoma (cancer) or lipoma
  • There’s no history of trauma

During this procedure, your healthcare professional will remove a small tissue sample. The tissue will be examined with a microscope to determine if the cyst is cancerous or not.

Treatment is based on the severity of the mucous cyst. Sometimes cysts may not require treatment and will heal on their own over time. Superficial cysts often resolve on their own.

Do not try to open or remove cysts at home to prevent infection or tissue damage. Frequent or recurring cysts may require further medical treatment.

Laser therapy and cryotherapy are used to treat mucous cysts that are not very severe.

To prevent recurrence — or to treat especially severe cysts — your healthcare professional may recommend surgical removal of the cyst or even the complete salivary gland.

Depending on the type and severity of the cyst, mucous cysts can take anywhere from a week to two years after treatment to heal.

Even after healing, the only way to ensure a cyst will not come back is to have it surgically removed. Avoid habits like lip or cheek biting to help prevent future cysts.

Recovering from a mucous cyst often takes time. You should occasionally check the cyst to make sure it does not become infected and does not get any larger. Warm saltwater rinses may help speed up the healing process.

If you’re a regular lip or cheek biter, you might also consider breaking these types of habits. Keep a journal and keep track of how often you bite — it’s most likely related to stress, anxiety, or boredom.

Once you’ve identified the triggers, you can try to find ways to stop biting your lips and cheeks. Chewing on sugarless gum is just one method you can use to satisfy the urge to bite without harming yourself.

While home remedies might be helpful in healing some mucous cysts, it’s important that you avoid self-diagnosis. A doctor can make sure the bumps aren’t related to something more serious, such as oral cancer.

It’s important to consult a doctor if the cyst becomes large and uncomfortable. Though most mucous cysts are less than 1 centimeter in diameter, rare cases can result in cysts as large as 3.5 centimeters.

Smaller, painless cysts are often not detected unless you go to the dentist. This is especially true of mucous cysts that develop inside your mouth. A dentist may refer you to a medical doctor for a biopsy and other diagnostic tests.

In most cases, healthcare professionals will let a mucous cyst heal on its own. If the cyst is still there after two months, consider making another appointment with a healthcare professional.

Once identified and properly diagnosed, mucous cysts have a good recovery rate. These are benign (noncancerous) cysts, so they do not pose any long-term health concerns.

The greatest complications with mucous cysts are pain and discomfort. If you suspect a mucous cyst in or around your mouth, get it checked out promptly.