Withholding on lottery winnings works exactly like withholding on a W-2.
If you were under withheld, it may decrease your refund somewhat (or increase taxes due) If the winnings were over withheld, it may increase your refund.
Like a W-2, the only way you will get a full refund of your withholding(s) would be to have no taxable income.
To
get an estimate of your tax result and refund, see Tax Caster
