Did I ruin my tri ply pan??? Accidently placed hot tri ply stainless steel pan on mesh dryh drying mat

There are a few things you can try to remove the plastic. It won't be so easy, but if you stick with it, you can have hope to salvage your pan. The first thing I'd do is put it in the freezer. Then see if you can scrape or chip away the frozen and brittle plastic. Then I'd scrub away using either the baking soda, or a product called Bar Keeper's Friend, if you can find it. Failing that, perhaps plain old Comet or Ajax. You can also then try acetone nail polish remover. One other suggestion is to cover the spot with a bit of waste cloth, and apply a hot iron to it very briefly- and then quickly peel the cloth off, hopefully with the plastic. Once you have removed most of the plastic, a scrub with steel wool should remove any residue left. You might end up with a scar area, but it will certainly be easier to live with than the cost of replacing the pan.