Break the Matrix

hi,i've been using the belt facepulling technique where you fasten the belt to a pull up bar and then lean back and use your bodyweight as the pulling force but after a couple of weeks the left side of my neck was starting to hurt so i wrapped a sweater around my neck while doing it and the pain went away but now i feel the tip of my index finger of my left arm a little numb which i think comes from my neck..has anyone else experienced anything similar?

Yeah that is a reckless method. Let's say you weigh the average 70 kg / 150 lbs. Then consider how fragile  face and neck are. They are not made to withstand such forces. It's huge overkill, because facepulling works just fine with much lesser forces. Any extra force won't give additional benefit, but it does increase the risk of injury.

If you're cabable of pushing your posterior tongue on the soft palate and drive it through towards the roof of your throat, you probably won't need to facepull at all. You will start feeling pressure on your face almost immediately.