It provides protection, but it does not eliminate the risk entirely. I recommend an SPF of 30 or greater. Keep in mind that most people do not put on a thick layer when they use sunscreen, so they get less protection than I indicated above. The thing is, I am not a sun-worshipper. Maybe some basics here.
Moles are benign.
Sun exposure and heredity both play a role in causing moles, as well as other factors. People with an unusually large number of moles are at increased risk for melanoma, especially if a blood relative has had melanoma. Moles are primarily a concern if they are changing in size, shape, or color. In that case, a dermatologist should be consulted. People generally, and particularly people with lots of moles, should thoroughly examine themselves every month to look for any changes.