Health Flexible Spending Arrangements Improvements Act of 2012 - Amends the Internal Revenue Code to allow a distribution to a participant in a flexible spending arrangement (FSA) of FSA funds not used to reimburse medical expenses by the end of the plan year (currently, unspent funds must be forfeited). Limits the amount of such distribution to the lesser of: (1) $500; or (2) the excess of the salary reduction contributions to the FSA, over reimbursements for medical expenses for the plan year. Includes such distributions in the gross income of the FSA participant for income and employment tax purposes.