I don't know about your former preemie but mine has a high tolerance level to pain.
He can fall scratch up his entire leg pretty good and keep on running as if nothing has happened. He can come home from school with a big bruise and/or bump on his head and it won't phase him.
I remember his second day of kindergarten. I got a call from the teacher that my son tripped over a carpet and got a cut on his forehead. He needed stitches.
As I drove to go pick him up I thought he would be so traumatized. Nope...not one bit. When I got there I think the teacher was more distraught than he was! He was just sitting looking at books ever so calmly as the nurse held the cloth to his head to stop the bleeding.
Here is an article I wanted to share about Premature baby brains can't tell pain from touch.
I can't help but wonder if this study would also apply to our older preemies. Seems like it with my son.