A blister is a pocket of fluid that forms to cushion and protect skin after friction, a minor burn, or pressure. Most friction and small burn blisters heal on their own in 3 to 7 days — the best thing you can do is leave the blister intact (don't pop it), keep it clean, and cover it. When a blister becomes infected, comes from a blistering rash like shingles or cold sores, or you don't know the cause, a clinician can review your photos online and prescribe antibiotics or antivirals when appropriate.
Seek emergency care if: a burn blister is large (bigger than your palm), on the face, hands, feet, joints, or genitals, or looks deep or charred; you have widespread blistering, blisters with peeling skin or in the mouth and eyes, or signs of serious infection like spreading redness, red streaks, or fever.
See a clinician nowWhat blisters actually are
A blister is a raised pocket of clear (or sometimes cloudy or bloody) fluid that collects between the upper layers of skin. It forms to cushion and protect the tissue underneath while it heals. The most common causes are friction (new shoes, repetitive rubbing), burns (heat, scald, or sunburn), and pressure.
Blisters can also be a sign of something specific: a cold sore or shingles (grouped blisters on a red base), impetigo, an allergic contact dermatitis reaction (such as poison ivy), or certain skin conditions. The cause matters because it changes the treatment — an infected or viral blister needs more than a bandage.
What it looks like — common signs
If these describe what you're experiencing and you have no red flags, telehealth is a reasonable next step:
What to do right now
For an ordinary friction or minor burn blister, simple protection is best:
- Leave it intact — an unbroken blister is a sterile, natural bandage. Resist the urge to pop it.
- Clean gently with mild soap and water and pat dry.
- Cover it with a clean bandage or a padded blister cushion to reduce rubbing.
- Protect from friction — change to better-fitting shoes or socks, or move the cause.
- If it opens on its own, wash gently, apply a thin layer of plain ointment, and keep it covered while it heals.
An intact blister is your skin's own sterile bandage. Cover it, protect it from rubbing, and let it heal — don't pop it.
How a clinician can help online
For minor friction and burn blisters, and for blistering rashes, telehealth works well. A clinician reviews your symptoms and photos, confirms the likely cause, and gives clear wound-care guidance. If the blister is infected, they can prescribe topical or oral antibiotics; if it's a viral cause like shingles or cold sores, an antiviral works best started early. They'll also tell you if the blister needs in-person attention.
Telehealth is NOT the right path for: large burn blisters or burns on the face, hands, feet, joints, or genitals; deep or charred-looking burns; widespread blistering or blistering with peeling skin or sores in the mouth and eyes; or serious infection (spreading redness, red streaks, fever) — these need urgent in-person care.
How blisters are treated
Most friction and minor burn blisters need only protection and time. Infected blisters are treated with topical or oral antibiotics. Viral blisters (cold sores, shingles) are treated with antivirals, ideally early. Allergic blistering (like poison ivy) may be calmed with a topical or oral steroid. Large or complicated burn blisters and deep wounds are managed in person, sometimes with professional drainage and dressing.
How long does it last?
A typical friction or minor burn blister heals over 3 to 7 days as new skin forms underneath and the fluid is reabsorbed. Larger blisters and those from burns can take longer. Blistering rashes like shingles follow their own course and heal faster with early antiviral treatment. A blister that isn't healing or is worsening should be evaluated.
Frequently asked questions
Should I pop a blister?
In most cases, no. An intact blister is a sterile, protective covering while the skin heals. Leave small friction and burn blisters intact, cover them, and let them drain on their own. Only a clinician should drain a very large or painful one.
What causes blisters?
Most come from friction, burns, or pressure. Others are from infections like cold sores, shingles, or impetigo, from allergic reactions like poison ivy, from sunburn, or from certain skin conditions. The cause guides treatment.
How do I treat a blister?
Clean gently, leave it intact if possible, cover it with a clean bandage or cushion, and protect it from rubbing. If it opens, wash, apply a thin layer of plain ointment, and keep it covered. Watch for infection.
When is a blister infected?
Increasing pain, spreading redness or warmth, swelling, yellow or green pus, red streaks, or fever. An infected blister should be evaluated promptly and may need prescription antibiotics.
Can blisters be evaluated online?
Yes. For friction or minor burn blisters, and blistering rashes like cold sores or shingles, a clinician can review your photos online, advise on care, and prescribe antibiotics or antivirals when appropriate. Large burns need in-person care.
