Help! String of vertical skin pulling under boob. (Photo)

Great question! Not to worry, what you are experiencing is referred to as Mondor's cords. Mondors cords are vertical bands visibly extending from below your incision to the lower chest area. These cords are irritated veins just under the skin that can accompany any type of breast surgery. The treatment is anti-inflammatories and warm compresses. These cords may take up to few months to fully heal. 

Hello, thank you for your recent question and photos. What you are seeing and feeling is Mondor's cord which is inflammation of the vein.  This will get better and resolve on its own over time.  Best of luck!