A new mole or spot appears and keeps changing
A mole becomes asymmetrical
The border of a mole becomes irregular, ragged, or blurred
The color is uneven or changes, with multiple shades
The spot is larger than about 6 mm, though smaller lesions can still be cancer
A mole or spot grows quickly
A sore does not heal within a few weeks
A spot bleeds, crusts, or scabs repeatedly
A bump is shiny, pearly, waxy, or translucent
A red, scaly, or rough patch persists
A firm, raised, or tender lump develops
A dark streak appears under a fingernail or toenail
A mole itches, hurts, or feels different
A spot looks unlike your other moles
A lesion appears on sun-exposed areas such as the face, ears, neck, scalp, chest, back, arms, or legs
A lesion appears on the palms, soles, under nails, or mucous membranes
You notice any skin change that is new, growing, or not going away
A dermatologist should examine any suspicious or changing spot