Need some reassurance --, could this cause check engine light? Options

[mgnt232]

So i got headers for my ST almost a month ago, and the second o2 sensor has just been dangling because I never bothered to put in a bung.
So yesterday, I was driving and my check engine light came on (I was driving like a d*** with my friend ), anyhow nothing really seemed to be affected, and I drove to the gas station and home fine.
So when I was looking for anything obvious, I found my o2 sensor sitting kind of inside the rear engine mount... pulled it out and it was smooshed! (assuming it got stuck in there, and the engine tweaked a little when I was driving not so cautiously-

Anyway I disconnected my batteries, and plugged in the o2 sensor I originally bought to screw into the downpipe's o2 bung that I never bothered doing.
Started it up, and the light is gone. I reset my air/fuel ratio after that (followed the steps in the how-to section)
At idle it runs alot better now too

Just wondering if a smooshed o2 sensor would throw a code? thanks