Man warns against 'dangerous' tanning injections after turning so dark he 'looked like Madge from Benidorm' and now has the freckled skin of a 60 year old How to Tell the Difference Between a Mole and a Freckle The Dermatology Specialists Photographs of people with freckles highlight their beauty National Geographic Freckles develop when specific skin cells produce extra melanin in response to sunlight. When ultraviolet rays reach the skin, melanocytes release melanin to protect deeper layers from damage. In some people, certain Freckles vs. Moles: Differences and Similarities