Do I need a second lift? (Photo)

It is not unusual for that scar to ride up like that even without weight loss. Simple enough to revise if you want

Yes, you are having some bottoming out. do not go larger since you are not supporting this size well. You need to go down in size and may need mesh for support.

would recommend another breast lift. This may also require placement of internal support as that appears to be a rather large implant that will need more support than just skin. You may need some internal support as well such as Galaflex. I would find a surgeon certified by the American Board of Plastic Surgery; ideally, one with an aesthetic fellowship accredited by The Aesthetic Society. I would also review before/after photos, Google reviews, and talk to the surgeon directly if possible.