Dermatologists now believe that regularly exposing the face to the light and electromagnetic radiation from smartphones can damage the skin.Doctors claim they can even tell in which hand a person holds their phone from which side of the face looks most damaged.Dr Simon Zoakei, medical director of the Linia Skin Clinic in London , said: "Those who take a lot of selfies and bloggers should worry. Even the blue light we get from our screens can damage our skin."I think there is a gap in the market for products which protect, because ... people who take lots of selfies, and bloggers, come to me. I have seen there is damage and ageing taking place."It's a different wavelength, so sunscreen will not block it."Dr Zein Obagi, of the Obagi Skin Health Institute in Beverley Hills, said: "Your cellphone will damage your skin . It's not documented, but in my clinical observation I can tell whether someone uses their right hand or left hand to hold their phone. You start to see a dull texture ." - ©The Daily Telegraph, London..