Battery made my screen pop out of my Apple Watch gen 2. What am I able to do since it’s out of warranty?

Old Lion batteries can swell at the end of their useful life. Unfortunately, your watch can't be repaired and will need to be replaced. You can buy an Out of Warranty replacement watch, but given a Series 2 watch is now so out of date, it would not be a very wise investment. It would make more financial sense to buy a newer, more modern Watch, like the newer SE or Apple Watch 7 and recycle the old watch.

Please immediately stop using the watch and power it off completely.