An early melanoma may be perfectly circular, uniformly black in colour and only a few mm wide. Just a BLACK DOT !
That’s why you should check your skin at least monthly to look for “NEW” spots.
Take some “selfies” of your own skin to help pick the newbies (which may end up being badies) !
That’s also why you should see a real expert (i.e. a Dermatologist) to tell the bad (malignant) from the good (benign) ones to avoid unnecessary surgery and scars.