You can do an amendment to include the additional $3,000. If you will be adding $3,000 the IRS allows you to deduct qualified medical expenses that exceed 7.5% of your adjusted gross income for 2017. However, it is important to note that if you did not itemize you will not be able to add this to your return. If you did itemize, then you can add this, as mentioned, by an amendment.
If you are expecting a refund for the return you have already submitted, wait for that refund to be sent to you before completing the amendment to prevent delays. The steps and form you will need to complete the amendment are in the TurboTax FAQ at the end of this answer. Please select 'see entire answer' to read all the information.
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