I just realized I have a 1098-E for $114.32 student loan interest paid to lender. I missed this tax return document the first time around. Do I need to file an amendment?

No, not really! For an "above the line" deduction like student loan interest it probably won't change your tax return (if so then very little).  I would hold on to the document and do nothing right now.  If you do need to amend your return for some other reason, then add this 1098-E for 114.32 at that time.  

The tax on $114.32 even at 25% tax bracket is less than $30.  IRS does use tolerances (which are not made available to the public) This would definitely be below that threshold. 

However, If you do decide to amend your return then you can follow the directions listed below:

https://ttlc.intuit.com/replies/3318732