While a tan may give you the skin you desire, it's important to be aware of the potential side effects. First and foremost, a tan is a sign that your skin has been damaged by the sun. This is because UV rays can cause premature aging, wrinkles, and even skin cancer. So, it's important to be careful when you're exposed to the sun and to make sure you're using sunscreen with an SPF of at least 30. In addition, some people may experience an allergic reaction to the UV rays or to the products used in a professional tanning service. This can cause redness, swelling, itching, and even blistering. If you experience any of these symptoms, it's important to see a doctor right away.