Why is this specific scar I have so much more painful when I hit it off things compared to any other scar or body part?

Wow, sorry, this question was hard to word.

I was in a car accident in July that left me unscathed except for a gash on my knee that I sustained while crawling out of the window and dragging my knee across glass (car was upside down). In the ambulance, the paramedics suggested that I go to a hospital and have them cut the chunk of skin off, because it appeared to be just hanging there, and it was a large chunk. After a few hours and taking a shower and getting it cleaned up, I saw that it was not detached and to remove the chunk of skin would have been to cut the skin in two separate places, not something I wanted to do. Because of the amount of glass that was on every part of my body, they also thought there could be some glass in there and I should have it checked out for that reason as well.

Well, I was on a trip so I never did. I don’t personally think there is glass in my knee because I think I’d have felt it at some point, and I haven’t.

Here are some pictures:
Right after it happened
Later in the healing process

As you can see it is a fat, chunky scar.

Anyhow, since this has happened, and because I am generally clumsy by nature, I have smacked my knee, on the scar specifically, off enough things to know that it hurts infinitely worse than bumping any other body part with equal force off of the same object. I am simply curious why this is. Generally it hurts so bad when I hit it, I either scream, grunt, clench my teeth, bite my lip, something. I literally have to do something to get through the pain! And not only that, it doesn’t go away soon after like it normally would on an undamaged body part. It seems to resonate, and get worse over the course of a minute or so. I don’t have a particularly low pain tolerance and I’ve given myself enough injuries over the years to know that I’m not just being a baby.

I just don’t get it. I am simply wondering if someone can explain it to me. Or has had a similar experience? I have had a lot of nice sized scars but none of them have been this deep, or chunky, so I feel that may have something to do with it. Thanks for your thoughts in advance!