Sun blisters are second-degree burns, meaning both the outer and middle layers of your skin have been damaged by UV exposure. They typically heal on their own within one to three weeks if you care for them properly. The single most important rule: leave the blisters intact. That fluid-filled pocket is your body’s natural bandage, protecting raw skin underneath while new tissue forms.
Why Sun Blisters Form
When UV radiation penetrates deep enough to damage both the epidermis (outer layer) and the dermis (the layer beneath it), your immune system kicks into emergency mode. It floods the area with fluid to cushion the damaged tissue and prevent further injury. That raised, fluid-filled bubble is the visible result. It hurts because the dermis contains nerve endings that are now exposed to irritation, and the inflammatory response amplifies that pain signal.
Cool the Skin First
As soon as you notice blistering, get out of the sun and start cooling the area. Run cool (not cold) water over the burn or apply a damp cloth for 10 to 15 minutes. Ice and ice packs are too harsh and can damage the already-injured tissue further. Repeat the cool compresses several times over the first day whenever pain flares up.
Take an over-the-counter anti-inflammatory like ibuprofen early. It reduces both pain and the swelling that makes blisters feel tight and throbbing. Starting it within the first few hours gives you the most benefit, since inflammation peaks in the first 24 to 48 hours after the burn.
Do Not Pop the Blister
This is the step most people get wrong. Popping a sun blister removes the sterile barrier protecting the raw dermis underneath. Once that seal breaks, bacteria from your hands, clothing, or the environment can reach damaged tissue that has no intact skin to defend it. The result is a burn that was going to heal in a couple of weeks turning into an infection that takes longer, hurts more, and can leave a scar.
If a blister breaks on its own (from friction with clothing, for example), don’t peel the loose skin off in one piece. Instead, use clean, small scissors to carefully trim away the dead skin. Gently wash the area with mild soap and water, apply a thin layer of antibiotic ointment, and cover it with a nonstick bandage. Nonstick dressings are important here because standard gauze will bond to the moist wound surface and tear new skin cells away when you change it.
Daily Care While Blisters Heal
Keep the blistered area clean and moisturized. Aloe vera gel (pure, without added fragrances or alcohol) soothes the surrounding sunburned skin and helps retain moisture. Petroleum jelly works well directly over intact blisters to reduce friction. If blisters are in an area that rubs against clothing or shoes, cover them loosely with a nonstick bandage during the day and let them breathe at night.
Drink more water than usual. A significant sunburn pulls fluid toward the skin’s surface, which can leave you mildly dehydrated. You may not feel especially thirsty, but your body is using extra fluid for the healing process. Aim for several additional glasses per day until the burn resolves.
Avoid further sun exposure on the affected area entirely. New skin forming beneath a blister has zero UV protection and will burn almost immediately. If you need to be outside, cover the area with loose clothing rather than relying on sunscreen, which can irritate broken or blistered skin.
What Not to Put on Sun Blisters
Skip butter, coconut oil, and any thick, greasy home remedy. These trap heat in the skin and can worsen the burn. Avoid products containing lidocaine or benzocaine (topical numbing agents often found in “sunburn relief” sprays), as they can cause allergic reactions on damaged skin. Hydrogen peroxide and rubbing alcohol are also too harsh. They kill healthy cells along with bacteria and slow the healing process. Plain mild soap and water is all you need for cleaning.
Signs of Infection to Watch For
Most sun blisters heal without complications, but infection is the main risk. Check the area daily for these warning signs:
- Pus or cloudy drainage. Clear fluid inside a blister is normal. Yellow, green, or foul-smelling discharge is not.
- Red streaks spreading outward. A ring of redness around the blister is expected, but streaks radiating away from the site suggest the infection is moving into surrounding tissue.
- Increasing pain after the first two days. Burn pain should gradually improve. If it suddenly worsens on day three or four, infection is a likely cause.
- Fever. A temperature over 103°F (39.4°C) with vomiting after a sunburn requires immediate medical attention.
When Sun Blisters Need Medical Care
Most small sun blisters on the arms, legs, or back can be managed at home. Certain situations call for professional treatment. Large areas of blistering that cover a significant portion of your body may need prescription burn cream and specialized dressings. Blisters on your face, hands, feet, or over joints deserve extra caution because scarring in those areas can affect appearance or movement.
Systemic symptoms point to a more serious burn response. If you feel dizzy, nauseated, extremely fatigued, or develop a headache with muscle cramps alongside blistered skin, your body is struggling to manage the damage. Babies and young children with any degree of blistering sunburn should be seen by a doctor promptly, as their skin is thinner and more vulnerable to complications.
Healing Timeline
Most sun blisters go through a predictable progression. The first two days are the worst for pain and swelling. By days three through five, the fluid inside the blister begins to reabsorb and the bubble flattens. Around the one-week mark, the outer layer of dead skin starts to peel naturally. New, pink skin is visible underneath. Full healing, including the point where the new skin no longer looks noticeably different from the surrounding area, takes two to three weeks for most people.
The new skin that forms will be more sensitive to UV damage for several months. Even after it looks fully healed, the area is at higher risk for burning again. Use broad-spectrum sunscreen with SPF 30 or higher on the area once it’s fully closed and no longer tender, and reapply every two hours when you’re outdoors.