According to doctors who operated on him, Michael Jackson had many plastic cosmetic surgeries (on his face) and most of them were even considered inappropriate.
For example, Surgeon Dr. Wallace Goodstein (who operated on him in the 1990s) revealed this:
"[Michael Jackson] had multiple surgeries … He came in approximately every two months. It was about 10 to 12 surgeries in two years, while I was there … [He] had multiple nose jobs, cheek implants and he had a cleft put in his chin. He had eyelid surgery … He had so many things that were inappropriate…" (Dr. Wallace Goodstein, PEOPLE Interview)
Michael Jackson had his first nose plastic cosmetic surgery in 1979 not because he fell down and broke it during rehearsals, but because he simply wanted at that time a thinner nose as revealed by his personal vocal coach Seth Riggs.
Also, certain sources close to him revealed that the singer did not want to look like his father Joseph Jackson, which also explains why he resorted to so many plastic cosmetic surgeries (on his face) over the years.