New job’s background check

I recently applied for a new job in the same career field I’m in. I’ve been to two interviews and they both went great. I even received a job offer and now they are doing my background check. The problem is, on my résumé and background check... I *embellished* one of my previous job employment dates. I put an earlier start date and I actually quit the job after two years of being there for about 10 months. I got rehired but shortly after, felt major company/corporate changes so I pulled the plug once more. The problem is, I did not interpret that whole ordeal on paper or in person.... 😬

Now, the hiring assistant is inquiring for clarification on the date discrepancies because she contacted my old job and of course got different information. 😓 I’m feeling super guilty because I don’t want to get the job offer revoked because I’m really pumped on the company but I’m not sure how to explain myself after having two interviews and going through the application process.

Does anyone have any advice to handle this situation? I know people occasionally fluff info on résumés and job applications but it usually doesn’t bite people in the ass 😞