Michael Douglas, playing Liberace, has a facelift partway through the HBO movie. His skin is noticeably tighter and smoother afterwards. How was the effect achieved?
Make-up, possibly with prosthetics
From this interview with Vulture about playing the role:
In his long, over 40-year career—playing everything from Gordon Gekko, a titan of Wall Street (for which he won the Academy Award for Best Actor), to the philandering husband in Fatal Attraction to a compromised cop in Basic Instinct to a pot-smoking novelist in Wonder Boys—Douglas has always been a Zeitgeist-y embodiment of the modern man. Which means he has never worn prosthetics in a movie, let alone a rhinestone-encrusted floor-length fur cape decorated with sequins. “I was the girl on this movie! The hair and makeup for Liberace took two and a half hours,” Douglas said. “I’ve never done elaborate hair and makeup before. Up until now, my entire career has been contemporary.”