My employer sent a W2C with just box 12 corrected, DD, it was off by $3,000. Do I have make an amended return now?

If box 12 code DD was changed on your W-2C form but box 1 has not changed, then you do not need to file an amended tax return.

That’s a relief, thank you so much. Do I need to do anything with the form or just keep with my records? 

Just keep the corrected W-2 form for your records. The DD in box 12 is the amount that your employer paid for your health coverage. It has no effect on your tax liability. Please see the IRS topic Reporting Employer-Provided Health Coverage on Form W-2 for more information.

@zsacord 

Thank you so much @SharonD007