A few months ago I shaved off a goatee (well, a Van Dyke, but who cares) that I’d had for about fifteen years. I noticed right away that the outline where my beard used to be was clearly visible after a day’s stubble growth; I chalked it up to extra contrast due a lack of tanning on that area.
Since then my face has caught up with the rest of my tan, and I’ve recently started growing the whole beard out again. After a couple of weeks’ growth, the sides of my old beard are still plainly visible against the rest of the hair. What could be the cause of this? I was thinking maybe a lack of friction or sunlight might have allowed the follicles there some sort of advantage over time, but that’s just a guess.
I don’t believe it matters but I have a possible explanation for it. I used to shave daily and it took me all of about 45 seconds to do it every morning even though I have a rather thick beard because one day’s growth is easy to shave and keeps the hair right at the surface or even slightly below it.
However, I went a rare week this week and didn’t shave the entire time so I developed a quite noticeable full beard. I have rarely gone that long between shaves before. It was time for it to go this morning so I broke out the razor. The first one took off most of the longer hairs but quickly dulled and started to snag so I switched over to new razor #2. That one did the intermediate work but it took about 15 minutes to get to the point where I would normally look after missing even 1 day of shaving and that razor started to get dull as well so I switched to razor #3. I used that one to get completely shaved like I normally would but it took a while. If I shave again tomorrow, it will take me about 45 seconds like it did before but, if I wait a few days, it is going to be an ordeal to get back to a smooth baseline again.
My point is that it takes time and effort to get back to that smooth baseline once you allow facial hair to grow much at all. It sounds like you didn’t reach that point and may not want to but you can if you shave multiple times in a row making sure you are using a sharp razor at every step.
It has long been my observation that the “goatee” or “van dyke” portion of many men’s beards are the thickest, most densely haired part of their beard. So shaving/not shaving isn’t really going to affect it that much, it’s more noticeable because of characteristics of the hair produced.
no, it’s not possible for “more hairs to grow” on your body. Every hair follicle you have, you’ve had since birth. It’s just at/after puberty that some of those follicles start producing thicker, darker hairs. Shaving don’t have nothin’ to do with it.
Indeed, that’s the original motivation for wearing facial hair in that style—shave off the parts of the beard that don’t look as dull and thick.
Huh. Well it’s good to know I’m not imagining it at least. 
I’ll probably just chop it back down to where it used to be because this stuff on the sides looks like craaaaap.