You are still in early healing and this may be nothing other than asymmetric swelling. You can talk to your doc about some downward pressure exercises or straps. I bet you will be fine.
It is only 1 month post surgery. The left implant has not fallen into place which is what you're describing. Usually, the higher implant falls symmetrically, given enough time. Massaging the implant downward, adjusting your bra and wearing an upper pole breast band can all help the process.
Four weeks is far too early to evaluate symmetry due to the presence of swelling, muscle tightness, etc. Give yourself at least 3 months before evaluation.
I think you are noticing just your natural assimetry, nothing is going wrong with the implants settlement.
However, I'd have never used such broad base implants in you, they obviously do not fit into your ribcage, symmastia is a hair far.
There are some exercises you can do to try to help the implant come down into the pocket, you should check with your surgeon about his or her recommendations for doing this and how often, etc. It is not unusual for one side to take a little bit longer and of course there is still some swelling that will subside over the next few months.
Thank you for your picture. You do have some very mild asymmetry. It may be due to swelling. You're only four weeks from surgery. I would allow two additional months of healing before you judge the final results.
Even though still early I believe you are in a fixed position. If after 3 months post op still asymmetrical than consider revision with or without fat grafts...
It is not uncommon for the implant to take 3 months to drop and usually one will drop before the other. Be patient and follow your plastic surgeons instructions.