How does hair grow back after shaving?

I know this topic was already created, but it was 2 years ago and I wanted some updated information on this subject. I posted already on the previous topic, but I will copy and paste my response here for more clarification on this.

This all started when I was in 6th grade. My mom didn’t allow me to wear pants so I was always wearing dresses. Since I wasn’t shaving I had a lot of people pick on me. I’m very pale and my hair is black, so imagine the horror I had to deal with. Due to this I not only started on my legs but decided that the hair on my stomach was next.

The thing is that the hair wasn’t bad at all, barely visible, but as long as I saw it it had to be removed. I removed mostly the hair below my bellybutton as a test. Soon enough the hair started coming back thicker. This wasn’t an illusion. The hair on my stomach was a light brown color, almost blonde, now it’s black and coarse. I even plucked it to compare to the hair I hadn’t shaved yet. I wanted to see if it truly was an illusion. It wasn’t. There is no way you can tell me this never happened because the hair is clearly damaged and much much coarser. So in attempts to even this out and experiment more I shaved above my belly button, but not all the way. Once my hair started to grow back there was an obvious difference once again between that hair and the one I didn’t touch. Even in the areas below my belly button that I didn’t change are very light and just fuzz. I strayed a couple of times and those hairs grew back thicker and darker.
I want to know what is the explanation behind that. There is no way it’s an illusion because people I’ve known, including doctors have mentioned there was a clear difference. I’m some kind of freak, lol.
Can anyone give me an actual answer.