Cancer Research UK says too much UV radiation from the sun or sunbeds can damage the DNA in skin cells. If the DNA builds up enough damage over time, it can cause cells to start growing out of control, leading to skin cancer.
There are two main types of UV rays. Both types can cause skin cancer - UVB and UVA.
Sunburn is a clear sign that the DNA in your skin cells has been damaged by too much UV radiation. Sunburn doesn’t have to be raw, peeling or blistering. If your skin has gone red in the sun, it’s burnt.
The above video, by Cancer Research UK, explains what happens to skin when it becomes sunburnt.
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Kerrie brings you Sunday night's forecast
Clear weather develops overnight into Monday. Cold days and frosty nights. Mainly dry inland - but a wintry risk continuing in the east
Icy first thing and windy, with wintry showers lingering further south, especially at the coast. Brighter elsehwere