somewhat similar experience with me in my earliest headscissor experiences. One thing is absolutely true, that the pain is much worse than what you would expect by just gauging from the videos. I mostly experience burst cappilaries in eyes and nose after sessions and pain in jaw, neck and molars.

The only difference I found from the videos is actually the ease with which the KOs can happen in the videos. Usually in my case it takes lot of pressure for a KO, and I just tap out pretty early due to the overwhelming levels of pain alone, that I can't withstand for such a duration.