Hi! Thank you for your question! This spot that you describe can be an abnormal skin pigmentation, that is benign of its nature and can remain like this for a long time. The only thing that you need to be careful is if the lesion changes its shape, color, irregular border, or if it bleeds. In case this happens you should visit a dermatologist and do a dermoscopy. If the spot does aesthetically disturb you, you can talk with your physician to excise it, or do a laser treatment. I wish you good health! Feel free to contact me again if anything is unclear. Dr. Gega