Those rated 15 to 30 block most of the sun's harmful rays. The most common warning sign of skin cancer is a change on the skin, especially a new growth or a sore that doesn't heal. Skin cancers don't all look the same. The cancer may start as a small, smooth, shiny, pale, or waxy lump, or it many appear as a firm red lump. Sometimes the lump bleeds or develops a crust.
Skin cancer can also start as a flat, red spot that is rough, dry, or scaly.
Both basal and squamous cell cancers are found mainly on areas of the skin that are exposed to the sun such as the head, face, neck, hands, and arms. However, skin cancer can occur anywhere. The cure rate for skin cancer could be 100 percent if all skin cancers were brought to a doctor's attention before they had a chance to spread. Therefore, people should check themselves regularly for new growths or other changes in the skin. Any new, colored growths or any changes in growths that are already present should be reported to the doctor without delay.