Can a benign Nevus grow back if excisional biopsy did not 100% remove it although it was removed completely to the naked eye? How long would it take?
Yes it can
Although benign microscopic melanocytes not seen by the naked eye can continue to grow and multiple around the original scar. If a pathology was obtained and showed moderate to severe atypia (abnormalities) then re-excision with clear margins microscopically is recommended.