Caitlyn Jenner -- It's Written All Over My Face ... This Doctor's Amazing (PHOTO)

Caitlyn Jenner's flaunting the handiwork of her plastic surgeons -- posing with one of the docs who was crucial to her transformation.

Caitlyn and Dr. Harrison Lee held up the now famous Vanity Fair cover shot for the pic. As Caitlyn said in the VF article ... she underwent 10 hours of surgery in Beverly Hills to feminize her face.

She autographed the mag for Dr. Lee -- saying, "Great job. Thank you so much."