Until you shed, the hairs that will shed may seem to appear a but darker. So, you may have extra shadow for a week or two before you see WAY less shadow.
The redness fades surprisingly quickly, a few hours is right, but it does feel like an instant sunburn for a while after which may make you think the red will last longer than it ultimately does. I wouldn't fret it.
As others have eluded, it does not all come out after one session, patches tend to remain. And I mean patches. Like it may look like the tech missed entire sections if you let it grow out. It is weird. And those patches may hold out for a few sessions, too.
Here are a couple examples. The first is what I natrually grew. Pretty burly. My beard used to grow fast!
This next one is after my first session and shedding, and then letting it grow out for a week because I was curious to see what was left. This was a day or two before shaving it all and going in for my second session. As you can see, gray hair is untouched, but a LOT of the dark was zapped away, and yet, little patches were untouched. I wish I got more angles because it left some interesting patterns. I was told, the area below and behind the jaw can be more resilient than others, it certainly was for me.
