Cyanoacrylate is a moisture cure adhesive. You have lots of moisture in your skin which helps it cure.
Cyanoacrylate is used in medical glue because it bonds so well with skin. Depending on the cut/injury, the medic may apply glue instead of stitches.

It's doing its job. Don't use acetone, it's bad for you.

I scrape it off with a Stanley knife blade.