How UV Rays Damage Skin
The sun's ultraviolet rays penetrate the outer layer of your skin and damage the genetic material (DNA) inside your skin cells. This damage triggers your immune system to react, causing inflammation. Your body tries to protect itself by sending extra blood to the damaged area, which is why sunburned skin looks red and feels warm to the touch.
The Inflammatory Response
When your skin is damaged by UV rays, your body releases chemicals called cytokines that increase blood flow to the area. This increased blood flow causes the redness and swelling you see with a sunburn. The inflammation is actually your body's attempt to heal the damage and prevent infection. This is why sunburned skin often feels hot, tender, and painful to touch.
Peeling and Healing
As your skin heals over the next week or two, the damaged outer layer of skin dies and peels off to make room for new, healthy skin underneath. This peeling is a natural part of the healing process. You should avoid picking at peeling skin, as this can cause infection and scarring. Underneath the peeling skin, new skin cells are being created to replace the damaged ones.
Cellular Damage and Mutation Risk
Beyond the visible burn, UV rays can cause mutations in skin cell DNA that may not show up immediately. These mutations can accumulate over time with repeated sun exposure, increasing the risk of skin cancer later in life. This is why even sunburns that heal completely can have lasting consequences. Protecting your skin from the sun throughout your life is important for preventing skin cancer.
Different Skin Reactions
Not everyone experiences sunburn the same way. People with lighter skin tones burn more easily because they have less melanin, a protective pigment that absorbs UV rays. People with darker skin tones have more melanin but can still get sunburned and experience UV damage. Regardless of skin tone, everyone needs sun protection because UV damage increases skin cancer risk for all skin types. 
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