Empress Marie Feodorovna's youthful looks were widely commented on during the early years of Nicholas II's reign. She was said to have had her face 'enamelled' - an apparently fearful process which involved the removal of the top layer of her facial skin. Her sister, Queen Alexandra, was also said to have endured the same process. The operation(s) were said to have been carried out either in Denmark during lengthy family visits or in the South of France. Exactly what this 19th century cosmetic surgery consisted of I have no idea. Perhaps another poster has information ?
Gladys, Duchess of Marlborough had a disastrous experience with a similar process in the early 20th century. Fanny Ward, the American actress, had better luck. But her apparent refusal to age made her a figure of fun in the 1920s - particularly in the classic book "Gentlemen Prefer Blondes" by Anita Loos.