Lump on my dog’s leg

Hello. I just noticed my dog has been licking a spot on his leg and was losing his fur around there from his excessive licking and realized there was a pink lump there. It doesn’t seem hurt him since he lets me touch it but he does lick it a lot constantly. Can anyone tell me what this is? He’s around 13 years old. Thank you! 

Hello!  That might take a biopsy to identify and could theoretically be cancerous (either malignant or benign) or inflammatory (a reaction to something, such as a small foreign body in the skin).  I can see how much your dog has been licking from the colour that the saliva turns the fur and this can be a sign of pain, or simply that it's annoying him.  A vet visit - and possibly even biopsy or removal - may be in order.