What is causing the "ledge looking," flatness on the bottom of my breast? (photos)

Thanks for the pics and ? I'm not sure or your entire history, but I'm guessing you have had an operation before this one. The ledge you are referring to is probably from where the breast pillars were approximated to reinforce the lower pole and provide stability for the implant. I suspect this will smooth out over time. The picture that would be helpful is one that is straight on without your arms extended (No Selfie). I don't see a lot to correct and would wait a minimum of 6 months before even considering a revision. This should be discussed with your surgeon. Best of Luck!