3 weeks out from surgery... if you have any visible changes in the appearances of your breasts or symptoms, you should see your surgeon for an exam and explanation of what is going on. If you've had the bubbles from the beginning and its improving, then you're headed in the right direction.
Healing will go on for 2-3 months for the early period. There may be some swelling, bruising, malposition, color differences. Sensation will be abnormal. Scars will be changing.
If my patients have concerns that something is unusual about their healing process, it is important for them to call the office and discuss these concerns or come in to be examined. While it may or may not be air bubbles causing a bruised feeling, there is still more time for you to allow complete healing and settling of the implants. I would recommend that if you have any questions or concerns about healing, then you see your surgeon in person for evaluation of the healing process and make sure all is going well. Best of luck to you!
You sound like you are having a normal recovery, especially this early after surgery. Air bubbles do not cause a bruised feeling.