I already did my taxes, but I received a 1098-T from my school for what I believe is a tuition reimbursement

[bryanearle16]

How do I continue and return to my tax return?

[DoninGA]

If you have e-filed your tax return and need to change, add or delete information on the tax return then you will need to wait for the tax return to either be accepted or rejected by the IRS.
If the tax return is rejected then you can make your changes and re-file the tax return.
If the tax return is accepted then you will have to amend the tax return to make your changes. An amended tax, Form 1040X, return can only be printed, signed, dated and mailed by you to the IRS, it cannot be e-filed. The IRS will take up to 4 months to process the amended tax return. Wait until you have received the tax refund or the taxes owed have been paid and processed by the IRS before amending the tax return.

[Hal_Al]

The 1098-T is only any informational document. The numbers on it are not required to be entered onto your tax return. 

However receipt of a 1098-T frequently means you are either eligible for a tuition credit or deduction or possibly you (or your student dependent) has taxable scholarship income.  So, you don't need to file an amended return just because you got a 1098-T. But will need to amend to claim a tuition credit or report scholarship income.

Tuition reimbursement is not reported, per se, on a form 1098-T (it may be reflected in the difference between the numbers in boxes 1 & 5.) Employer provide tuition reimbursement is tax free, up to $5250, and is usually included on your W-2.