Several millimeters. To completely remove a mole, one must cut into the skin as the mole may extend several millimeters below the surgace. This will require a stich. However, sometimes we only wish to remove the protion of the mole that sticks out and bothers the patient: in this case we can"shave" the lesion flat parallel to the surface of the skin.
Let a plastic. Surgeon do it. Freezing might a br a good choice too.
Mole removal. Any time you cut the skin you will have a scar. You can minimize scaring by preventing sun exposure during the healing process.