Try sticking it in the freezer. It might get cold enough that the plastic pops right off.
How Do I Remove Melted Plastic From My Stainless Steel Pot?
Heat your pan with water, but not to boiling point and add 2 tablespoons of baking soda. Scrape it off with a non-metal spatula carefully. This should do the trick.
I would wait for the plastic to harden then try to tap on the bottom with a wood spoon or a piece of would and see if it will break loose and fall out