The signs
Asymmetry, an irregular border, more than one colour, a diameter over six millimetres, and any change over weeks. One mole that does not match the others is worth a look even if it meets none of these.
Deeper skin is different
Skin cancer is less common on deeper skin but is found later, because it tends to appear on the palms, soles, nail beds and inside the mouth rather than on sun-exposed skin. A dark line under a nail that does not grow out with the nail should be checked.
At the clinic
The dermatologist examines the mole with a dermatoscope, photographs it for the record, and either reassures you, books a review, or removes it the same day with a local anaesthetic. Anything removed is sent for examination and the result is explained to you.
Related procedure: Mole removal
Read about mole removalThis article is general information from the dermatologist and does not replace a consultation about your own skin.