First off, if the lesion is changing (i.e. bigger, darker, raised, itching, etc), it should be evaluated by a dermatologist. Also if the lesion has any of the features of melanoma it should be evaluated by a dermatologist. ABCD stands for Asymmetry, irregular Border, varied Color, and large Diameter. If it is suspicious for melanoma (and you can't tell without an in-office evaluation), it should be removed or at least a portion of it should be sampled. Since the pigmented lesion is flat, shave or tangential excision will not work as well as excision to the subcutaneous tissue. The lesion would have to be excised, and the repair would be dependent upon the size of the lesion and possible adjacent loose tissue. Based on the photograph, a flap repair would be more likely as a side-to-side repair would likely distort the free margin of the eyelid. I would recommend that you see either a fellowship-trained Mohs surgeon, plastic surgeon or oculoplastic surgeon. Talk to the doctor about their experience in surgery and repair in this area.