Lied on previous SF-86 about expunged record.

Hello reddit,

In 2009 when I was a minor, I was charged with a felony in CA, but it was expunged after I did some community service.

I joined the military in 2015, and I had to get a Secret security clearance for my job. I lied on the SF-86 and said that I did not have an expunged felony, since I was told at the time that it wouldn't show up in a background check and also because I assumed that it would prevent me from joining the military if I listed the charge.

I passed my clearance check and was granted a Secret security clearance. I believe this means that the record was not found? The investigator didn't bring it up during our discussion.

In the time since then I have grown a lot, both mentally and professionally. I did 8 years in the military and then was honorably discharged. Afterwards, I worked as a defense contractor with a Secret security clearance. I am now applying for a new position that requires a Secret clearance, but since it's been ~10 years I need to do another SF-86.

I am now facing a moral dilemma that honestly makes me feel sick.

On one hand, I want to admit to the expunged felony on my new SF-86, but that would mean admitting to lying on my last SF-86, which from what I have read is almost a guaranteed denial. I want to admit to it and explain myself as I have above.

On the other hand, the expunged record didn't show up during my last clearance check and it's possible that the record is truly gone. In which case, admitting to it would be a giant self-own.

I'm ashamed that I lied and I want to come clean, but I am terrified at the prospect of losing my career over all this.

What do you all think I should do and what are the likely consequences.