PLA Sticking to Bed

I’m a noob at 3D printing— I got my Ender3 S1 a little under a month ago. I’ve had great success on multiple prints using mostly default settings, up until last week. I had adhesion problems and was told it was likely my nozzle. I tried a spare nozzle and my next two prints were perfect. Since then I’ve had nothing but messy, blobby unsuccessful prints. More concerning, the prints are sticking to the bed so badly that all I can do is brutally scrape the PLA off. I’ve tried using iso alcohol but it doesn’t make much of a difference. I’ve heard acetone can damage the bed, and I don’t want to make it worse if it’s salvageable.

1. Is my bed cover completely ruined?
2. What should I do to prevent this in the future?

Thanks in advance. This is my first post on Lemmy and it’s exciting to see how quickly this community is growing!