Face lift

The term "face lift" was used as a slang for regeneration by some Gallifreyans.

Upon becoming reunited with the Doctor, whom he knew in a previous incarnation, Runcible asked if he’d had a "face lift", to which the Doctor replied ‘several’. (TV: The Deadly Assassin)

Behind the Scenes

After her appearances in Dynasty, the First Rani referred to the Seventh Doctor as "Face lift No. 7", using the term as a synonym for incarnation. The Doctor claimed to accept her new demands for group therapy, more make-up and a hair stylist after she appeared in the series but couldn't stand her usage of this term above all. However, these events took place in a story which this wiki does not consider to be a valid source.

In the real world, a "face lift" is a colloquium used by humans to describe a hytidectomy, which is cosmetic surgery to lift up and pull back the skin to make the face tighter and smoother.