My employer is issuing a W2C showing overpaid wages from 2014 that I reimbursed them in 2015. Do I need to re-file my 2014 taxes or can I get a tax deduction in 2015?

I had received wages in error during unpaid personal leave in 2014.  I brought this to the attention of my employer in 2015 and repaid the appropriate amount (~$6000) to them.  They are now planning to issue a W2C and also asking for my consent to file 2014 OF W-2c to obtain a FICA refund on my behalf.  Does this mean I will need to re-file my 2014 income tax return as well?  The FICA taxes are a small amount and I would just prefer to reimburse that amount to my company directly rather than go through the hassle of re-filing 2014 taxes.  Also, can I get a deduction in my 2015 tax return for the amount I repaid my company?  Appreciate any advice on this topic.