Chosen Solution
There is little one can do to fix a dead or always engaged pixel. I would bring the system into Apple if it’s still under warranty. They should swap out your system (or display unit). Even if the warranty has expired you might be able to get them to fix it. You might need to demonstrate your need for a perfect display as it’s not uncommon for a few pixels to drop out over time. The more central in the display field pixel/s are, the more noticeable they are. If these are not in the center 1/3 of the display you’ll have a hard time getting them to fix it.
