they do make hot glue gun like tools for ptex, but you cant really use just a hot glue gun as glue sticks melt at a much lower temp so the guns don't get very hot.
you can also get a soldering iron style mender, my friend has one and says its much better for core and edge shots because you can spread a certain type of plastic directly on the core/edge that bonds much better to ptex
I personally just use a flame drip method on my skis, they are extruded so they are easier to repair, even a bad core shot stayed all of last season and I repaired them on an armchair in a hotel when the skis were still cold. On my skis with a sintered base I get core shots fixed by my local shop, they don't get scratched too easily because they are a pretty nice base.
repost by the way