Thanks so much for your question. I can see what you are describing based on your photo. Bottom line, it's not a good time to reoperate unless you were forced to do so by an infection or bleeding, etc. Malposition of the implant is not a reason to reoperate at this time even if there is a problem. I agree with you're surgeon's advice. I would want you to stay in an underwire bra. Things may improve enough with the bra that no further surgery would be necessary. You otherwise have a really nice result so hopefully the bra will lift things back into place and your body's own ability to heal will do the rest. Hope that helps.
From the photograph, but I'm assuming is in the mirror, it appears to me that the right breast is lower on the chest wall that on the left. However, the crease incision is right in the crease and the implant has not migrated beneath it. Without seeing your preop photographs, it certainly may be that this is a magnification of a small amount of preoperative asymmetry that you began with. I'm not sure how your plastic surgeon does the surgery, but when I do a breast augmentation, the only sutures that are placed are the in the incision used to place the implant. If one of the sutures popped with lifting it should not cause the implant to migrate lower unless it migrated below the old incision. I recommend you follow up with your chosen plastic surgeons' recommendations and stay in a bra until you can be seen. I wouldn't panic, I think everything on the okay. Good luck.