Painful Lump Under the Skin: Cyst, Abscess or Something Else?

Finding a new lump under your skin can be concerning, particularly when it becomes painful, swollen, warm, or red.

Sometimes the cause is relatively simple, such as an irritated cyst or inflamed hair follicle. In other cases, the lump may be an abscess, a skin infection, an inflamed lymph node, or another type of growth that requires medical evaluation.

The challenge is that several different conditions can look similar from the outside.

A painful lump should therefore be evaluated based on its location, appearance, rate of growth, tenderness, surrounding skin changes, and associated symptoms rather than assuming what it is.

What Can Cause a Painful Lump Under the Skin?  

Several conditions can produce a lump beneath or within the skin.

1. Epidermoid Cyst  

An epidermoid cyst is a closed sac beneath the skin that contains keratin, a protein found in skin cells.

These cysts are often:

• Round or dome-shaped

• Slow-growing

• Located just beneath the skin

• Initially painless

A cyst can become inflamed or infected, causing it to become painful, swollen, red, or warm.

Importantly, an inflamed cyst is not necessarily the same thing as an abscess. A healthcare professional may need to examine it to determine what is occurring.

2. Abscess  

An abscess is a collection of pus that develops within tissue, usually because of an infection.

It may appear as:

• A painful, swollen lump

• Red or warm skin

• Increasing tenderness

• A firm or soft center

• Drainage of pus

Some abscesses become progressively more painful over several days.

The Centers for Disease Control and Prevention (CDC) recommends medical evaluation for skin infections that are worsening, particularly when redness or swelling is spreading or other symptoms develop.

3. Inflamed Hair Follicle or Boil  

A blocked or infected hair follicle can develop into a painful bump or boil.

These commonly occur in areas exposed to:

• Friction

• Sweating

• Shaving

• Repeated skin irritation

A small follicle infection may resolve on its own, but a larger or increasingly painful lesion may require professional evaluation.

4. Swollen Lymph Node  

Not every lump beneath the skin originates from the skin itself.

Lymph nodes can become enlarged when the immune system responds to an infection.

Common locations include:

• Neck

• Under the jaw

• Armpit

• Groin

A swollen lymph node may be tender, particularly when it develops during an infection.

The location of the lump and the presence of other symptoms can help a clinician determine whether a lymph node may be involved.

5. Lipoma  

A lipoma is a benign growth made up primarily of fatty tissue.

Unlike an abscess, a lipoma is typically:

• Soft

• Movable beneath the skin

• Slow-growing

• Not painful

A new lump that changes rapidly, becomes painful, or develops other unusual characteristics should still be evaluated rather than assumed to be a lipoma.

Why Pain Changes the Picture  

Pain can provide useful information, but it does not identify the cause by itself.

A painful lump may reflect:

• Inflammation

• Infection

• Pressure on surrounding tissue

• Trauma

• Irritation

• Another underlying process

The American Academy of Dermatology Association advises people to seek medical attention for skin growths or lesions that change, become painful, bleed, or develop other concerning characteristics.

Signs That a Lump May Be Infected  

Pay particular attention if a lump develops:

• Increasing redness

• Warmth around the area

• Increasing swelling

• Worsening tenderness

• Pus or drainage

• Red streaking extending away from the area

• Fever or chills

These findings can indicate an infection that requires medical assessment.

Does a Painful Lump Always Need to Be Drained?  

No.

This is an important distinction.

Some people assume that every painful lump containing fluid should be squeezed or drained at home. That can make the situation worse.

If an abscess is present, a clinician may determine that drainage is appropriate.

However, the treatment depends on the size, location, depth, surrounding infection, and the patient's overall health.

Some lesions may instead require observation, medication, or another form of treatment.

Do not attempt to cut, puncture, or squeeze a painful lump yourself.

Doing so can potentially spread infection or cause additional tissue injury.

When Should You Visit Urgent Care?  

Consider an urgent care evaluation when a lump:

• Becomes increasingly painful

• Is growing noticeably

• Becomes red or warm

• Develops drainage

• Interferes with movement or normal activity

• Develops after an injury

• Is accompanied by fever

• Does not improve over several days

• Keeps returning in the same area

Urgent care can help determine whether the problem appears consistent with a superficial skin condition, infection, or another issue requiring additional evaluation.

When It May Be an Emergency  

Some symptoms require more immediate medical attention.

Seek emergency care if a skin lump or infection is associated with:

• Rapidly spreading redness or swelling

• Severe or rapidly worsening pain

• High fever with significant illness

• Confusion

• Fainting

• Difficulty breathing

• Signs of a severe allergic reaction

A rapidly progressing skin infection can occasionally become a serious systemic illness and should not be managed at home.

What Happens During an Urgent Care Evaluation?  

Evaluation generally begins with a careful history and physical examination.

A clinician may ask:

• When did you first notice the lump?

• Has it changed in size?

• Has the pain increased?

• Has anything drained from it?

• Have you had fever or chills?

• Did it develop after shaving, an injury, or an insect bite?

• Have you experienced similar lumps before?

• Do you have other symptoms?

The clinician may examine:

• Size and location

• Skin color and temperature

• Tenderness

• Consistency of the lump

• Whether it moves beneath the skin

• Whether there is drainage

• The condition of surrounding tissue

In some situations, ultrasound or another diagnostic test may be considered to determine whether a lump contains fluid or involves deeper tissue.

Why Diagnosis Matters Before Treatment  

A cyst, abscess, swollen lymph node, lipoma, and other types of lumps can require very different approaches.

For example:

A cyst may be monitored or treated depending on whether it is inflamed, infected, or recurring.

An abscess may require drainage.

A swollen lymph node may require evaluation of the underlying infection or inflammatory process.

A lipoma generally does not require urgent treatment but may warrant assessment if its characteristics change.

This is why treating every lump as an infection—or assuming every lump is harmless—can be misleading.

What You Should Not Do at Home  

Until the lump has been evaluated, avoid:

• Squeezing it

• Puncturing it with a needle

• Cutting the skin

• Trying to drain it yourself

• Applying irritating chemicals

Instead, keep the area clean and monitor for changes in size, redness, pain, drainage, or other symptoms.

What About a Lump That Does Not Hurt?  

Pain is not the only factor that matters.

A painless lump should also be evaluated if it:

• Continues growing

• Becomes firm or fixed

• Changes in appearance

• Bleeds or develops an open area

• Persists without an obvious explanation

• Is associated with unexplained systemic symptoms

Most lumps are not cancerous, but persistent or changing growths should not be self-diagnosed.

The Bottom Line  

A painful lump under the skin may be an inflamed cyst, abscess, infected follicle, swollen lymph node, or another condition.

The appearance of a lump alone cannot always establish the diagnosis.

Pay attention to how quickly it developed, whether it is changing, whether the surrounding skin is becoming red or warm, and whether you have fever or other symptoms.

If the lump is painful, growing, draining, or becoming increasingly red or swollen, medical evaluation can help determine what is causing it and whether treatment is necessary.

If you develop severe symptoms, rapidly spreading redness or swelling, significant fever, confusion, or difficulty breathing, seek emergency medical attention.

Trusted References  

• Centers for Disease Control and Prevention (CDC) — Skin infections, including signs that an infection may require medical attention.

• American Academy of Dermatology Association (AAD) — Guidance on evaluating changing, painful, or unusual skin growths.

• Mayo Clinic — Information on epidermoid cysts, skin infections, and when medical evaluation is appropriate.

• Merck Manual — Clinical information on skin abscesses and soft-tissue infections.