Edit: Great! You got it as I was rewriting this to not suggest exactly what worked...I was mostly afraid it would damage something and I’d have felt bad for advising it.
Original (rewritten before posting) message:
I was going to suggest sticking something long and sharp down the edge and trying to get it into one of the little gaps that appear to be there, but then I realized that you’d probably get it out easiest with something sticky.
Not sure what you have available, but put a little bit of it on the end of a pen or whatever and lightly touch the screen until you can get it to come up. Just try to make sure it’s non-toxic and still wash the screen and anything else the sticky part touches before using it again.
At least that’s what I’d probably do at this point, for fear of damaging the heater with other tools.