4 weeks post op. Double bubble? Swelling? (photos)

After 6 months this will likely stretch out and look very nice.  At 4 weeks it is too early to tell anything about the results.

I agree with the other surgeons who have responded that 4 weeks out is too early to accurately judge breast implant results.
But there are several things that suggest this will need surgical repair:
The abrupt contour change on the bottom of the breast. That indentation looks like a transition point between breast skin/tissue and chest skin that has been pulled forward and upward. That strongly suggests a double-bubble.The position of your scar. It appears to be the better part of an inch above the crease under your breast  (inframammary fold). This again suggests that your natural crease has pulled away from the chest wall. If you had a well-defined crease before your breast augmentation, that will produce a double-bubble.Your history of scar position asymmetry. This one is a little trickier because I don't know how symmetric your breasts were before your surgery but it does sound like the left implant settled into a lower position than the right.This indentation may improve as you heal but, most often, it will persist. It can be repaired by suturing the fold back into place, by using your own scar capsule to reposition the implant higher, or by placing a mesh support. 
You should wait at least six months from the original surgery before attempting to correct this. Allowing enough time for proper healing will improve the likelihood that your repair is successful.

Thanks for your question Shar86. There can be a lot of reasons for the double bubble image shown, including your suspicion about the double bubble. We have all seen results like this improve over the first 3-6 months post-op so it is important for your to be patient. It sounds like your PS is being very appropriate with their care, so stick with them. Best of luck!