if she isnt showing any kind of discomfort, acting strangely, or being lethargic, than I wouldn't worry about it, unless you are concerned with her aesthetic look, in that case I would do some research on what solutions you can do.
If she is acting normal and like her old self, eating, being active, but her only difference if the swollen pom, then I don't think there is too much to worry about, unless you are concerned with the aesthetic look of your goldfish.
no, dont attempt a surgery, if it goes wrong you could give copper an infection or worse, death. If you do want to do surgery on her make sure you have sterile, professional equipment, and education about fish surgery and this growth. I hope she turns out well in the end