Sunburn typically appears as pink or red skin that feels hot to the touch, tight, and tender. In mild cases, the redness is the only visible sign. In more severe burns, you may see blisters, swelling, or skin that looks wet or shiny. The appearance changes over the course of several days as the burn progresses through distinct stages.
Mild Sunburn: First-Degree Burns
A first-degree sunburn affects only the outermost layer of skin. On lighter skin tones, it shows up as an obvious pink or red flush across the exposed area, often with sharp lines where clothing or a swimsuit blocked the sun. The skin feels warm, tight, and tender when touched or when fabric rubs against it. Mild swelling can develop, especially on the face, nose, or shoulders.
On darker skin tones, sunburn can be harder to spot visually. The redness may not be obvious, but the skin will still feel hot, painful, and tight. The burn often only becomes clearly visible once peeling starts days later.
One important detail: sunburn doesn’t appear immediately. Redness typically starts around 3 to 4 hours after UV exposure and peaks at about 24 hours. So the burn you notice in the evening will likely look worse the next morning.
Severe Sunburn: Second-Degree Burns
A second-degree sunburn goes deeper into the skin and looks noticeably different from a mild one. The redness is intense, and the skin may develop fluid-filled blisters that range from tiny dots to larger, raised patches. The burned area often appears swollen over a wide region, and the surface can look wet or glossy. Some areas may show white discoloration within the burn, which signals deeper damage to the skin layers.
Second-degree sunburns are significantly more painful than mild ones. The blisters form because the deeper skin layers have been injured enough to separate, and the space fills with fluid. Breaking these blisters increases the risk of infection, so it’s best to leave them intact.
What Sun Poisoning Looks Like
Sun poisoning is a term for a severe sunburn that triggers a systemic reaction, not just local skin damage. It starts with a red rash and can progress to widespread blistering, severe swelling, and skin that looks bright red and may ooze. The burned area appears angrier and more inflamed than a typical bad sunburn.
What distinguishes sun poisoning from an ordinary burn is what happens beyond the skin. Fever, chills, nausea, vomiting, and headache can accompany the visible damage. The body is losing fluids and electrolytes through the damaged skin, which can lead to dehydration. If you’re seeing bright red, oozing skin along with any combination of fever, shivering, or nausea, that’s a burn that needs medical attention.
Why Sunburn Turns Red
The redness you see isn’t the burn itself. It’s your body’s inflammatory response to DNA damage in skin cells caused by UV radiation. When UV rays hit your skin, they directly damage the DNA inside skin cells, triggering those cells to die. Your immune system responds within about an hour by releasing inflammatory signals, including histamine (the same compound behind allergic reactions). These signals cause blood vessels near the skin’s surface to widen, flooding the area with blood. That increased blood flow is what creates the red color and the feeling of heat.
This is also why sunburn has a delay. The UV damage happens instantly, but the inflammatory cascade takes hours to fully develop, which is why the redness peaks a full day after exposure.
The Peeling Stage
Several days after the initial burn, the damaged skin begins to peel. This is your body shedding the layer of dead and damaged cells to make way for new skin underneath. A mild to moderate burn typically heals within 3 to 5 days, and the peeling phase lasts up to a week after that. Small amounts of skin can continue flaking off for days or even weeks in some cases.
During peeling, the skin looks dry, flaky, and uneven. Patches of dead skin lift away in thin sheets or small flakes, revealing newer, more sensitive skin beneath that’s often lighter in color. The new skin is more vulnerable to UV damage, so it needs extra protection from the sun. Resist the urge to pull off peeling skin, since tearing it can remove healthy skin along with it and slow healing.
How Sunburn Looks at Each Stage
- Hours 0 to 3: Skin may look normal or slightly pink. You might not realize you’re burning.
- Hours 3 to 12: Redness becomes visible and progressively deepens. Skin feels hot and tight.
- Hours 12 to 24: Redness peaks. Swelling and tenderness are at their worst. Blisters may start forming in severe cases.
- Days 2 to 3: Redness begins to fade. Blisters (if present) may grow or start to flatten. Pain gradually decreases.
- Days 3 to 7: Peeling begins. Skin looks dry and flaky as the damaged outer layer sheds.
- Weeks 1 to 3: New skin is exposed. The area may appear lighter than surrounding skin until pigmentation evens out.