It sounds like you left the withdrawal off your tax return completely, or else the tax and penalty would have been calculated.
If this was a tax-deferred account (contributions were tax free or tax deductible) then you always owe regular income tax on the withdrawal.
If this was an IRA, there is an exception to the 10% penalty for early withdrawal if you use the money to pay qualified higher education expenses for yourself, your child, or your grandchild. Qualified higher education expenses are for college or graduate school (nothing at or below high school level) and are for tuition, books and fees required by the school, and room and board if the student is at least half time. (This is a different definition of qualified education expenses than you would use for the higher education tax credits.) You have to report the withdrawal on your tax return, and indicate it was used for qualified higher education expenses.
If this was a pension, 401(k), 403(b), or some other plan NOT an IRA, there is no penalty exception for higher education expenses.
