For the itemized deduction on medical you would reduce the cost of the premiums by the reimbursement of $600. 

You are using the downloadable version of TurboTax so this would be very easy.

Go to the Forms mode in your TurboTax program.  (upper right in the blue area on a windows computer otherwise View on a Mac).

Open the Medical worksheet and on line 13a highlight it and enter $600.

This will fix this.