has gone under the knife.
The actress, 38, had "a small procedure" on her neck to correct a vertebrae she broke years ago, a source tells PEOPLE.
Posing for photos at Variety's 5th Annual Power Of Women
event at the Beverly Wilshire Four Seasons Hotel on Friday, Theron wore a cream-colored dress with a high neckline that covered the base of her neck.
Theron, who is mom to 22-month-old Jackson
, is "totally fine," the source adds. Next, she stars in Dark Places
, the film adaptation of Gillian Flynn's novel.
With reporting by JULIE JORDAN