Horizontal line between bottom of nipple and breast crease 4 days post Breast Augmentation?

Thank you for your question. An in person evaluation is required to answer your question. It is in your best interest to be seen by your nurse or surgeon to have your questions answered. Best, 

Dear Jessica,   Thanks for submitting your pictures. It would have been helpful to see your before and after pictures in full size. Being as it may, I see the mild indent that worries you, however,  it is very early in the healing process and it might be just due to swelling , which will subside in 2-3 weeks.   As far as implants displacement massage, it is a great idea. All my patients start it on the 3rd day after surgery, which is when the capsule (scar around implant) starts forming and it is soft enough to be stretched by the massage, creating soft and natural looking breasts.                   Best of luck,                                     Dr Widder

It is too early to definitively diagnose a double bubble.  If the inframammary crease was lowered to make room for a very large implant double bubble is a possibility.  However is best that you have an examination in person with your surgeon, not the nurse, to diagnose if double bubble has occurred.