I would say have another go at your GP. Our GP, for all their faults, are very pro-active regarding possible skin cancers. My husband thought he had a persistent patch of eczema behind his ear and showed it to our GP, who referred him to the 2 week wait dermatology clinic at Kings. Turned out to be a Basal Cell Carcinoma (BCC), which was removed within a few weeks. Since then, if my husband has any concerns about further patches, he askes the GP to refer him. So far, he has had 3 BCCs removed and is awaiting a further procedure.