What characteristics of a new or changed mole might be a sign of melanoma?

Moles and other skin marks should always be investigated by a board-certified dermatologist routinely (every year) since skin cancer can be quite deadly (at least with melanoma) and is becoming more common today. If a mole's appearance changes noticeably such as its color, its shape, if it becomes irregular in shape or around its borders, bleeds, or if you're really just unsure and want to make sure your healthy, visit your local dermatologist and get evaluated. It's not worth getting skin cancer.