Sounds like the dermatologist can't remove the mole and fail to biopsy it without incurring additional liability, but the cosmetic surgeon can legally and ethically tell the patient, "Look, I'm not a dermatologist, so I'm not making any attempt to diagnose this mole. If you want a clinical diagnosis, you must go to a dermatologist. As far as I am concerned, you are responsible for any health risk associated with removal or non-removal of this mole. I am just performing a cosmetic procedure at your request."