#1 - Actinic Keratosis - these dry crusty bumps are on sun damaged skin and can be either flat or raised in appearance. They occur after long periods of sun exposure and damage. They are not life threatening and can be treated with freezing (cryosurgery), excision or chemical peels.
#2- Basal Cell Carcinoma- this is the most common type of skin cancer and can usually be cured by removing it. They also occur in sun damaged skin.
#3- Solar Lentigo- This is a large freckle caused by the skin damage from UV radiation (sun). They are also called sun spots or liver spots or age spots as they occur in people over age 55 after years of sun damage.
#4 Squamous Cell Cancer-This is the 2nd most common skin cancer and it also occurs with sun damage. Men are twice as likely to have SQ cancer. Most are curable and they do not metastasize but they can spread and cause large areas of damage to the skin. Any non-healing sore on a sun exposed part of the body (ears, lips, nose, face) could be a squamous cell cancer.
Nobody got them all right.
Doctors love skin pics. Here is a site with lots of skin pics.