The difference in appearance of the scars is not alarming but should not be ignored. Discuss this with your surgeon. There are many options for scar management and treatment and the goals for both of you will be to minimize the appearance.
All scars do not heal equally
and that is what you are seeing. Now if the scar becomes bluish or translucent in appearance, you should see your surgeon about this.
During the healing of a scar, there is some inflammation, that shows as a red color on the scar, all scars go trough this, and last around 3 to 4 months for the inflammation to go away. Not all the scars have the same amount of inflammation, and that is what you see now, it is normal, and you can help using a silicone strip over the scar, that will apply some pressure on the scar to reduce the inflammation.
Best Scar Management is important to minimize or completely hide from view, the telltale signs of your surgery—namely, scars. Both you and your surgeon want you to have the most minimal scarring possible. There are many possible causes for scars that are enlarged or not healing well. Unsightly scars are most commonly due to genetics, underlying medical conditions, or improper scar/wound care. The last part is very important and patients can make a noticeable difference in their scars’ appearance by following best scar management practices.
Thank you for your question. At three weeks post op you are still early in recovery and you can expect your scars to mature/lighten over time. It is not uncommon for each side to heal at a slightly different rate. Closer to 6 months post op you can expect things to even out. Let your Plastic Surgeon know if you have ongoing concerns.
All the best