Concave spot on left breast (Photo)

If your implants are under the muscle, the muscle is usually released somewhat from your sternum in this area. The thinness could be the loss of some muscle there. If this bothers you, a fat transfer could be done. Please discuss this with your surgeon.

Dear johnson711,
I understand your concern. However, without a proper assessment, it would be difficult to determine what is wrong. It is best that you visit your plastic surgeon for further assessment or ask for a second opinion. Only after a thorough examination, you can get proper recommendations and advice.
Daniel Barrett, MDCertified, American Board of Plastic SurgeryMember, American Society of Plastic SurgeryMember, American Society of Aesthetic Plastic Surgery

Thanks for your question. We do see this kind of problem on occasion. If your implants are beneath the muscle, it appears that a small slip of muscle was left intact at that spot instead of being released smoothly along the sternum. As a result, the implant cannot fill this space out as evenly as it does on your other side. The area can be tender due to pulling on the muscle. It should be a fairly easy fix, but would require a quick operation to open the pocket up through your original incision and release this area where the muscle is still attached. Talk to your original surgeon and they should be able to advise you.