Sir/madam My Sister Has Swollen Like On Right Cheek From

Sir/madam my sister has swollen like on right cheek from last five to six years . no pain and also no increase in size . but it appears one side of the face is more than left side . I think probable cause is injury as she fell down from cycle 10 years back. She has injury under chin with stitches and on face. How can it be cured . she is 25 years old .