After you file

Sorry ... but you MUST report the refund you received in 2018 on the 2018 return form 1040 if you itemized deductions on the 2017 return.   

THEN ... the taxes you paid in  2018  to the state is a deduction on the 2018 Sch A .... you CANNOT net them against each other.  You are an unintended  victim of the new tax laws.