1. An image processing method performed by an image processing apparatus that generates, on the basis of a face image which is an image including a face of a person, a lip correction map representing a distribution of weights used in correcting a color of a lip included in the face image, the image processing method comprising the steps of: acquiring the face image; extracting a lip region, which is a region corresponding to the lip, from the face image; determining a representative color of the lip using pixels located inside the lip region; acquiring, for each pixel included in the face image, a first value representing a proximity to the lip region and a second value representing similarity of a color to the representative color; and generating the lip correction map on the basis of distributions of the first values and the second values.