Dog leg what is it?

Hi my dog has this thats come on her leg she keeps licking it any idea what it is and if so what I can get to help get rid of it? Many thanks 

Hello - this could be superficial dermatitis (surface skin inflammation), but that's a description of a symptom rather than a diagnosis or a cause.  Dermatitis can occur for countless different reasons but self-trauma due to allergy is quite a common possibility.  Others include burns, fleas, flies and mites, a thorn, pain in the limb or joint beneath (or further away if that's the closest that the pet can reach to lick), ringworm (not usually itchy, but infectious to people!), a friction wound and so on.  If lesions are continually licked, it shows that they are painful or irritating to the patient.  A big part of treatment is often relieving the urge to itch or lick because such lesions have a habit of spreading outwards.  A vet appointment might prove to be a good idea.