5'8, 130lbs, B to D/DD - flat areas on side of breasts since 6 months post-op, please help (Photos)

You are experiencing excess tissue expansion in the lower poles of the breast tissue despite the use of mesh, leading to these flat spots. You are very lean and with small native breasts, and you and your surgeon did not heed caution: smaller implants and subpectoral placement. As your tissues continue to expand and thin, you can expect rippling in the central chest and in the upper poles of your implants too, unfortunately. An in person examination would be required to make the best revision surgery plan, but at the very least you'll need re-tightening of the implant capsule with more mesh. If you are going back, think hard about placing the implants under the pec major muscle too.

These implants actually are too large for your frame and your tissue and may not look round or natural at this size. I would suggest going down in size and perhaps tightening the lateral pockets.