Get your taxes done using TurboTax

The premiums were taken out after taxes but was still listed in box 12a DD which from what I understand, is pretaxed items. My wages are the same in box 1,3 and 5.  It appears from what I’m reading, that box 12a lowers wages in box 1 but that is not the case on my w2.  Is there anything I can do to get this corrected?  I know nothing about this type of thing but this is going to cost me a lot of money on my return.