Hi . greetings. Moles are not commonly malignant and over time rarely they may turn malignant. However, whenever in doubt please see a dermatologist. He could examine it, do Dermoscopy and if necessary a biopsy to rule out malignancy. Usually moles are suspected to have become dangerous when they grow in size or change colour or itch etc. Send in your pic On follow up chat. Hope this helps. Warm regards Dr Govind S Mittal, Bangalore