All is Well
Thank you for your pictures. Your areola looks fine. If you had necrosis, you would not have capillary refill. The area would look black.
One nipple darker than the other after breast reduction
There are several possibilities as to why one nipple is darker than the other. It may simply be bruising. What is more likely however is venous congestion of the nipple and underlying tissue, which can happen during a reduction when blood flow to the piece of tissue which the nipple is connected to is not adequate to quickly drain the blood away. Often this will go away as the tissues heal and the breast re-establishes blood flow. Sometimes this can be permanent. It does not appear that you have necrosis, as this is apparent pretty immediately after surgery, and the nipple in this case would look a lot darker, almost black.
Left nipple darker than right after breast reduction. Is this normal?
Congratulations on having undergone the breast reduction procedure. The darker nipple/areola complex may be a sign of venous insufficiency. In other words, the darker side may not be draining the venous outflow as well as the lighter side. Best to make sure that your plastic surgeon is aware of the situation; he/she will always be your best resource when it comes to accurate assessment, advice, and/or meaningful reassurance. Best wishes for an outcome that you will be very pleased with
One nipple darker after breast reduction
Your left nipple ok at this point, perhaps with some venous congestion. Make your operating surgeon aware of this so they can follow it along with you to be sure things move in the right direction.
Normal Post Op Changes following breast reduction
It appears that your are healing normally. The slight darker area may represent some mild reversible venous congestion that is often seen following this procedure. Please check with your plastic surgeon should you have a concern.