Effetto greenscreen sfocato ai bordi per la pelle.

Hi, I am relatively new in the field, I state that I need to ask this question for urgency of use, I do not practice a strong use of after effects but for work I need to know how to use some of its features, in particular the post production effects from greenscreen, I state that I know how to use this function basically, I would need to take advantage of the blur effect on the sides of a green background, in words it is difficult for me to describe it so I will attach an example image, this effect I would like to use on the skin through adhesive tape, I have to cover lines which are seen due to stage costumes during the shoot, I used the blur effect on after effects with the masks but it takes a huge amount of time and I came up with this idea of using masking tape on the lines of the costumes to cover them, thank you kindly who will be able to give me a quick indication.