Updated on February 1, 2024
5 min read

Bump Inside Lip (Mucous Cyst)

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What is a Mucous Cyst?

An oral mucocele or mucous cyst is a harmless, fluid-filled bump inside the mouth. It’s often caused by trauma or salivary gland blockage and is the most common noncancerous salivary gland lesion.

Mucoceles can develop anywhere on the buccal mucosa. This area includes:

  • Lips
  • Gums
  • The roof of the mouth
  • The underside of the tongue

The lower lip is the most typical site, usually due to lip biting.1 When mucoceles develop on the floor of the mouth, they are called ranulas.

Ranulas are more common in older adults. If they are large enough, they can cause problems with speech, swallowing, and even breathing.

Signs and Symptoms of an Oral Mucous Cyst

If the mucocele is near the skin’s surface, it may appear as a swollen, fluid-filled sac with a bluish tinge. If the mucocele is in a deeper layer, it may appear more round and white.

They usually have the following characteristics:2

  • Painless
  • Movable
  • Soft
  • Round or dome-shaped
  • Translucent with a red, pink, or blue tinge
  • 2 to 10 mm in size

Symptoms may depend on the extent of the mucocele, but most are uncomfortable rather than painful. However, if they recur frequently or occur more deeply in the tissue, they may become more tender.3

What Causes Oral Mucous Cysts?

Trauma or salivary gland blockages cause mucoceles. Lip biting is the most common traumatic cause of mucous cysts. Other causes include:

  • Cheek biting
  • Cheek or lip piercings
  • Rupture of a salivary gland
  • Friction from teeth
  • Poor dental hygiene

Some people can develop oral mucous cysts as a bad reaction to tartar-control toothpastes or frequent mouth washing with hydrogen peroxide.

Who Is at Risk of Oral Mucous Cysts?

Mucoceles are most common between the ages of 10 to 25 but can occur at any age. They also occur equally as often in females and males.4

When to See a Doctor

You should see a doctor if you notice swelling in or around your mouth. You should also get professional treatment if the cyst interferes with important functions like breathing, talking, or eating.

In most cases, mucous cysts are small, painless, and harmless. You may not know you have a mucocele until you visit the dentist.

If your dentist finds a cyst, they may refer you to a doctor for testing and diagnosis. They can rule out anything serious.


Doctors diagnose mucous cysts based on clinical symptoms. They may ask if you bite your lip or have experienced other trauma to your mouth. They will then physically examine the cyst.

A doctor may recommend a biopsy if the cyst’s appearance is suspicious or there are no obvious causes. They will send the tissue sample for laboratory analysis to determine what cells are present, then they can present a diagnosis.

Professional Treatment

Your doctor decides on the best treatment based on the cyst’s severity and your symptoms. If cysts recur frequently, your doctor may recommend medical treatments:5

  • Laser therapy — involves using a targeted beam of high-power light to remove the cyst under local anesthesia.
  • Cryotherapy — the doctor freezes the cyst using liquid nitrogen, which is extremely cold and destroys the mucocele. 
  • Intralesional corticosteroid injection — these steroid injections reduce inflammation and accelerate healing.

If you have reoccurring, severe, or painful cysts, your doctor may recommend a more complex surgical approach, such as removing the salivary gland.

Following treatment, it can take several months for a mucous cyst to heal, depending on its type, location, and severity. 

Complications from Treatment

Treatment of oral mucous cysts has a good recovery rate with few complications or long-term issues.  Some complications during surgical removal of oral mucosal cysts include: 

  • Hemorrhage
  • Nerve damage

In some cases, you could experience the following issues after treatment:

  • Infection
  • Recurrence 
  • Scar tissue 
  • Reopening of the surgical wound

Home Remedies for Oral Mucous Cysts

There are no effective home remedies for lesions like oral mucous cysts, and they often heal independently. Recovery is only a matter of time, but it’s best to check the cyst regularly to ensure it hasn’t grown larger or become infected.

Some people find that warm salt water rinses help accelerate the healing process and prevent infection. It is also important to see a doctor to ensure it is not related to anything more serious, like oral cancer.

It’s important not to attempt to drain or remove cysts at home. This practice increases the risk of infection and tissue damage.

How to Prevent Oral Mucous Cysts?

Once a cyst has healed, the best way to prevent reoccurrence is to avoid mouth trauma. If you have a habit of lip biting or cheek chewing, you need to find out why.

If you bite your lips because of anxiety or nervousness, ask your doctor for stress-controlling techniques or a referral for behavioral therapy.6

Your doctor may also recommend reducing the use of certain toothpastes or mouthwashes that can irritate the mouth and cause mucosal cysts.

Occasionally, oral mucous cysts happen by chance and cannot be prevented. If they are an ongoing problem, the only way to prevent them may be to remove the salivary gland surgically. 


Oral mucous cysts are benign, fluid-filled sacs that can develop in the mouth. They’re usually painless and cause no other health problems.

Most oral mucous cysts don’t require treatment and resolve independently with time. If a cyst recurs or is tender, doctors can treat it with steroid injections, laser therapy, cryotherapy, or surgery.

If you develop swelling or growths in your mouth, see a doctor. They can accurately diagnose the condition and rule out any serious causes.

Last updated on February 1, 2024
6 Sources Cited
Last updated on February 1, 2024
All NewMouth content is medically reviewed and fact-checked by a licensed dentist or orthodontist to ensure the information is factual, current, and relevant.

We have strict sourcing guidelines and only cite from current scientific research, such as scholarly articles, dentistry textbooks, government agencies, and medical journals. This also includes information provided by the American Dental Association (ADA), the American Association of Orthodontics (AAO), and the American Academy of Pediatrics (AAP).
  1. Chaitanya et al. “Mucocele on Lower Lip: A Case Series.” Indian dermatology online journal, 2017.
  2. Nallasivam et al. “Oral mucocele: Review of literature and a case report.” Journal of pharmacy & bioallied sciences, 2015.
  3. Huzaifa et al. “Mucocele and Ranula.” StatPearls publishing, 2022.
  4. Kim et al. “Concurrent occurrence of mucocele and pyogenic granuloma.” Annals of dermatology, 2011.
  5. Seo et al. “Oral Mucocele of Unusual Size on the Buccal Mucosa: Clinical Presentation and Surgical Approach.” The open dentistry journal, 2012.
  6. Kubo et al. “Mastication as a Stress-Coping Behavior.” BioMed research international, 2015.
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