You should not amend your return. If the return which you filed has been accepted, then there is no need to amend the return. The IRS will check their records with the amount you entered and will adjust your return accordingly. However, if the amounts do not match, then there will be significant delays before you received your refund.
If the return which you filed, gets rejected for any reason, then you can fix the amount and file again.
To check the amounts you entered, please refer to Line 30 on Form 1040 which will show you the amount of credit included in your refund.
