First, I compared the portrait I treated slightly with the portrait after the skin was modified.
After modifying the skin before modifying the skin
Open the photo in Photoshop, click the background in the lower right corner to create a new layer (the first step in processing the image must be done first-create a background copy). Then click on the magnetic Lasso tool after local amplification, on the arm along the edge of the click (Note with the sideline left a certain space, feather value can be set between 10-20, not too large), the delineation after the filter-Gaussian blur (fuzzy radius I set is 5.8, the value can be used, note that the setting is too large.) I can do a contest, feel almost on the line) and then click OK.
(photoshop tutorial figure 1)