A tooth infection typically starts as a persistent, throbbing pain that can range from a dull ache to sharp, intense pulses radiating through your jaw. Unlike the brief sting of a cavity, the pain from an infection tends to linger, worsen over time, and eventually spread beyond the tooth itself. How it feels depends on how far the infection has progressed.
Early Signs: Sensitivity That Won’t Quit
Before a full-blown infection sets in, the first warning is usually heightened sensitivity. You might notice a sharp twinge when drinking something cold or eating sweets. At this stage, the inner tissue of the tooth (called the pulp) is inflamed but not yet infected, and the sensitivity fades within a second or two. Many people brush this off as normal tooth sensitivity.
As the inflammation worsens, the sensations change in a telling way. Sensitivity to heat appears, and pain from hot, cold, or sweet foods lingers for more than a few seconds instead of disappearing quickly. The pain may shift from sharp to a deep, throbbing ache. This is the point where the damage to the tooth’s inner tissue is becoming permanent, and a bacterial infection is either underway or close behind.
In some cases, a tooth that has been hurting suddenly stops. This can feel like relief, but it usually means the nerve inside the tooth has died. The infection is still there, it’s just no longer triggering pain signals from that nerve. The quiet phase doesn’t last. Once the infection spreads to the surrounding bone and tissue, the pain comes back, often worse than before.
What Abscess Pain Feels Like
Once bacteria form a pocket of pus around the tooth root, you have a dental abscess. The hallmark sensation is a throbbing pain that follows your heartbeat. It can be constant or come in waves, and it often intensifies when you lie down because blood pressure in your head increases. Many people find it impossible to sleep on the affected side.
The tooth itself may feel tender, loose, or slightly raised in its socket. Biting down or even lightly tapping the tooth can send a jolt of pain through your jaw. Pressure of any kind, including clenching your teeth or chewing, makes things worse. Some people describe a feeling of fullness or pressure deep in the gum, like something is building up underneath.
If the abscess ruptures on its own, you’ll notice a sudden rush of salty, foul-tasting fluid in your mouth. The taste and smell are unmistakable. The pain often drops dramatically right after, because the pressure has been released. But a ruptured abscess hasn’t healed. The infection still needs treatment.
Pain That Spreads Beyond the Tooth
One of the most confusing aspects of a tooth infection is that the pain doesn’t always stay in your mouth. The nerves serving your teeth, jaw, and ear are closely connected through a major nerve pathway called the trigeminal nerve. When a tooth becomes infected, irritated nerve signals can be interpreted as pain in a completely different spot.
This referred pain commonly shows up as an earache on the same side as the infected tooth. You might also feel it as a dull ache along your jawline, pressure behind your eye, or a headache concentrated on one side of your face. Some people visit their doctor for an ear infection or sinus problem before discovering the real source is a tooth. If you have unexplained one-sided ear or jaw pain, especially alongside any tooth sensitivity, it’s worth considering a dental cause.
Visible Changes in Your Mouth
A tooth infection often leaves physical clues you can see or feel. The gum tissue around the affected tooth may become red, swollen, and tender to the touch. In some cases, a small bump appears on the gum near the tooth root, sometimes called a gum boil. This bump is essentially the abscess pushing toward the surface, and it may occasionally leak pus or fluid.
Your gums might also pull away from the tooth slightly, making it look longer than usual. Persistent bad breath or a bitter, metallic taste in your mouth is common even when the abscess hasn’t ruptured, because bacteria are actively producing waste products in the infected area.
When Infection Starts Affecting Your Whole Body
A tooth infection that stays localized is painful but manageable with dental treatment. The situation becomes more serious when the infection begins to spread. The first systemic sign is usually a fever of 100.4°F (38°C) or higher, often accompanied by fatigue and a general feeling of being unwell.
Swelling is another key indicator. An infection from an upper tooth can cause your cheek or the area below your eye to puff up noticeably. A lower tooth infection may cause swelling along the jawline or under the chin. The swollen area typically feels firm and warm to the touch, and the skin over it may look flushed.
At this stage, over-the-counter pain relievers often stop working. The pain may become severe enough that maximum doses of common painkillers barely take the edge off. This combination of uncontrolled pain, fever, and visible swelling signals that the infection is outpacing your body’s ability to contain it.
Red Flags That Need Immediate Attention
Certain symptoms indicate the infection has spread to dangerous areas and requires emergency care, not a dental appointment. Difficulty swallowing is one of the most critical. When infection spreads to the tissues of the throat or the floor of the mouth, swelling can compress the airway. Difficulty opening your mouth fully is a related warning sign.
Other emergency symptoms include swelling that extends to the upper half of your face or neck, difficulty breathing, double vision or changes in eyesight, drooping eyelids, severe headache, confusion, nausea, and vomiting. These signs suggest the infection has reached deeper tissues, blood vessels, or spaces near the brain. They are rare, but they develop faster than most people expect, sometimes within hours of swelling first appearing.
What Happens at the Dentist
If you go in suspecting an infection, the exam is straightforward and mostly involves reproducing your symptoms in a controlled way. The dentist will likely tap on the chewing surface of the suspected tooth and then on its inner and outer sides, asking whether each tap triggers pain. This percussion test helps pinpoint exactly which tooth is involved, especially when the pain has been radiating and you’re not sure where it started.
You may also be asked to bite down on a small instrument to see if pressure causes a pain response. Temperature tests, where a cold or warm stimulus is applied to individual teeth, help determine how much damage the inner tissue has sustained. A tooth that reacts intensely to heat but not cold, or one that doesn’t respond to any temperature at all, tells a different story than one with mild cold sensitivity. X-rays complete the picture by showing whether infection has spread to the bone around the tooth root.
Treatment depends on the stage. Earlier infections may be resolved by cleaning out the damaged tissue inside the tooth. Advanced abscesses often require draining the pus, antibiotics to control the bacterial spread, and in some cases, extraction if the tooth can’t be saved. Most people feel significant relief within a day or two of treatment, though complete healing of the surrounding tissue takes longer.