A lump on your jaw is most often a swollen lymph node reacting to a nearby infection, but it can also come from a dental abscess, a blocked salivary gland, a skin cyst, a benign bone growth, or (less commonly) a tumor. What’s causing yours depends on exactly where it is, how it feels, and what other symptoms you’re experiencing.
Swollen Lymph Nodes
This is the single most common reason people notice a lump along the jawline. You have a chain of lymph nodes running just under your jaw, and they swell whenever your immune system is fighting something nearby: a cold, a sore throat, an ear infection, or even a skin wound on your face. A reactive lymph node typically feels tender, moves when you press on it, and is roughly pea- to marble-sized. It usually shrinks back to normal within two to four weeks once the underlying infection clears.
Lymph nodes that feel hard or rubbery, don’t move when you push on them, keep growing over several weeks, or appear without any obvious infection are worth getting checked promptly. Those characteristics can signal something more serious, including lymphoma or a cancer that has spread from another site.
Dental Abscesses
An untreated cavity, a cracked tooth, or old dental work can let bacteria reach the inner pulp of a tooth, creating a pocket of infection at the root tip. That infection often produces a visible lump on the gum or along the outer jawbone near the affected tooth. The hallmark is a severe, constant, throbbing toothache that radiates into your jaw, neck, or ear. You may also notice sensitivity to hot and cold, pain when chewing, a foul taste in your mouth, or swelling in your cheek or neck.
A dental abscess won’t resolve on its own. Left untreated, the infection can spread into the surrounding bone or soft tissue. If you have facial swelling combined with fever or difficulty breathing or swallowing, that’s a situation requiring urgent care.
Salivary Gland Stones
Your submandibular glands sit just below the jawbone on each side, and they’re the most common site for salivary stones. These are small, hardened mineral deposits that block the duct carrying saliva into your mouth. The telltale sign is swelling and pain under your jaw that gets worse when you eat or even think about eating. That’s because the gland ramps up saliva production at mealtime, but the stone won’t let it drain, so pressure builds.
Between meals, the swelling often goes down partially or completely. If you notice a lump under your jaw that swells and shrinks in a pattern tied to eating, a salivary stone is a strong possibility.
Skin Cysts and Lipomas
Not every jaw lump is deep. Two common culprits sit right beneath the skin surface.
A skin cyst (often called a sebaceous or epidermoid cyst) is a small sac filled with fluid or semi-solid material. It feels firm, like a tiny balloon under your skin, and may have a visible dot or opening at the center. It can sometimes become red and inflamed if irritated or infected.
A lipoma is a slow-growing collection of fat cells between the skin and muscle. It feels soft, rubbery, and doughy, and it slides easily under your finger when you press on it. Lipomas are almost always painless and harmless, though they can be removed if they bother you cosmetically or keep growing.
The quickest way to tell them apart: a cyst feels firm and may be slightly anchored in place, while a lipoma is squishy and moves freely.
Benign Bone Growths
Sometimes the lump is literally part of the bone. An osteoma is a slow-growing, benign bony bump made of mature, well-differentiated bone. On the lower jaw, these tend to appear near the angle (the back corner), the molar area, or the inner surface behind your lower front teeth. They feel rock-hard because they are bone, and they’re attached firmly to the jaw rather than sitting in the soft tissue above it.
Most osteomas are painless and discovered by accident during a dental X-ray. They’re most common in young adults and affect men and women equally. Unless one is large enough to cause bite problems or facial asymmetry, it typically doesn’t need treatment.
TMJ-Related Swelling
The temporomandibular joint sits right in front of your ear, and inflammation there can sometimes produce what feels like a lump. Jaw joint disorders are usually recognized by jaw pain, stiffness, clicking, or difficulty opening your mouth fully. Facial swelling from TMJ problems is uncommon, but it does happen, particularly with arthritis in the joint or an infection within the joint space. In a study of 201 people with TMJ disorders, those who had joint swelling were also more likely to have enlarged lymph nodes and swollen salivary glands on the same side.
Jaw Cysts and Tumors
Several types of cysts and tumors can develop within the jawbone itself. Most are benign. They often grow slowly and may not cause any symptoms until they’re large enough to show as a visible lump, shift your teeth, change your bite, or cause numbness. Some are painless; fast-growing ones tend to be painful. Even benign jaw tumors can eventually change the structure of your jaw or damage nearby teeth if left alone, so they’re typically removed surgically once identified.
Signs That Need Prompt Attention
Most jaw lumps turn out to be harmless, but certain features raise the stakes. See a healthcare provider if your lump:
- Persists beyond two weeks without improving
- Feels hard, fixed, or immovable when you press on it
- Keeps growing steadily over time
- Comes with mouth sores that won’t heal, red or white patches inside your mouth, loose teeth with no dental explanation, difficulty swallowing, or trouble opening your jaw
- Appears alongside unexplained fever or weight loss
Jaw cancer is uncommon, but its early symptoms overlap with many benign conditions: a painless lump, displaced teeth, a changing bite. The distinguishing factor is usually persistence. Benign reactive swelling improves within weeks. Lumps that don’t improve, or that come with sores or patches in the mouth lasting more than two weeks, warrant evaluation. Diagnosis typically involves imaging (X-rays, CT scans, or ultrasound) and sometimes a biopsy to examine the tissue directly.