Should I come out clean to the background check about start and end dates?

So I lied on my resume about my dates. I worked for employer #1 up until this year. I'm currently on employer #2, but I left #2 out of my resume because I did not want it to seem like I was job hopping nor know who I worked for. My resume says I worked for #1 up till presently.

I have a background check but I just don't know if I should come clean about what happened and say that I was actually working at #2 for a few months, or if I should just stick with my story of working at #1 still?

Any help is super appreciated!