Wow, how complete and clear was everything you explained, @criptoitaly. As I read the nail example, I could perceive each of the sensations you described. You impressed me with the children with CIPA and their painless behavior of things. It's almost a horror story. In my environment I have known people who tolerate pain quite a lot: what can hurt someone normally, these people do not produce anything. It must be a minimum CIPA grade they possess. Similarly, I remembered reading about any lump or ball that may come out of our body that is painless, it can be more dangerous than the ones that hurt. For example, when we see painless breast inflammations, they can be more lethal than painful ones.
I feel that with this reading I have learned a lot and you have already become my favorite doctor. Thanks to you for the information and @adsactly for always bringing quality content.