There's a black hole in the center after I squeezed a pimple on my back.

It was a pimple I shouldn't have squeezed, but I did, and now a dark scar has formed...

It was a pimple that had festered inside, so I couldn't squeeze it—and I wasn't supposed to—but I kept touching it with my hands, and before I knew it, I found myself squeezing it.

I thought it would heal well, but after some time passed, I looked at it and saw a black hole in the center, and it healed just like that...

I can't squeeze it again, and although it has healed, how should I manage a scar like this?