Researchers have found both UVA and UVB rays “cause sun damage in the form of basal cell carcinoma and squamous cell carcinoma (two forms of skin cancer)," says dermatologist Lisa Ginn. Ginn also noted that other research suggests UVA rays may be behind melanoma, the most severe form of skin cancer.

"Sun damage can cause broken capillaries on the face and around the nose," says cosmetic dermatologist Sameer Bashey. Exposure to the sun reduces elastin, collagen, and the thickness of the dermis layer, so red and irritated-looking capillaries can rise to the surface and skin damage becomes more evident.

When UV rays land on the skin, directly or indirectly, it immediately makes an impact, altering the skin's DNA and eventually killing off skin cells. The body then increases blood flow to the skin's surface to deliver immune cells to heal the damage, making the skin red and painful and causing what we all know and loathe: a sunburn.

Skin aging is inevitable, but sunscreen can prevent skin from aging faster than it should. A study in which participants wore sunscreen every day for over four-and-a half-years showed that their skin didn't appear to age in response to the sun, and overall, their skin was 24% less likely to show signs of aging at all.

Age spots are also part of the aging process, but without sunscreen, they can appear with more frequency and visibility. While age spots aren't always dangerous, keep an eye on them to see if they change over time; if they get bigger, turn black, or are irregularly shaped, they could be a sign of damage and/or cancer.