Is there anything I can do to bring my breasts closer together? More cleavage, etc. 3 weeks post op. (Photo)

These questions are best addressed by your operating surgeon. However, generally speaking under the muscle has initially less cleavage unless the operating surgeon takes measures to position the sub muscular implants closer to the midline--- as I would do. Without this manuever it will take massage to stretch the muscle in the middle so that you will improve your cleavage.

Thank you for the question and pictures. No, I do not think that your preoperative pictures demonstrate  characteristics seen with tuberous breasts. I also do not think that there is anything that you can do to “bring your breasts closer together”. In my opinion, staying away from heavy pec major exercises (such as bench press, push-ups, flies...) may help prevent breast implants from shifting to the side. Despite your starting anatomy, it is possible (in my opinion) that the use of larger/wider breast implants may be helpful in achieving  decreased space between the breasts ( if you are considering revisionary breast surgery down the line). Best wishes.

Cleavage width depends on your pectoral muscles and how wide apart they are.  Some women have a naturally wide cleavage.  If you look at your pre pictures, you had a wide-spaced medial border.  Going over the muscle with a wider base implant may be an option, or simply a push up bra can help