For women with moderate to severe breast sag, a breast lift (mastopexy) may be recommended to ensure the best result and longest lasting result. Failing to have a breast lift when necessary will only lead to a less than ideal result leaving the patient unhappy and needing a revision surgery. A larger breast implant can help lift the breast, but the low hanging breast tissue will still be present causing a disconnect between the implant and breast tissue located at the bottom of the breast.Costs will depend on several factors: the geographic location, the skill and experience of the surgeon, and operating room and anesthesia fees. Different implants may have different costs. Approximate costs can be found on this website, Surgery.org, or PlasticSurgery.org. The best thing to do is to schedule a consultation with a local surgeon to discuss the desired revision that you would like and determine what the best procedure would be, the approximate cost and all details involved. The final results are not a definite answer beforehand, so careful planning can be done to make sure that everything turns out better than before. Good luck!
Sorry for the issues that you are having with your implants. One could guess and suggest several reasons why you might be having these issues, but an evaluation in person will give the most information to the surgeon to give an appropriate possible reason.