Forgot to include form 1042-s

I am a student on a F-1 visa (nonresident alien), working with a Teaching Assist at my University. I did my 2019 taxes using Sprintax with the information from my form W-2 and I got a refund of $609 (that what it shows the form 1040-NR-EZ I sent to IRS).

After mailing the documentation to IRS, my University sent me the form 1042-S that apparently I was supposed to use when doing my taxes, but I didn’t. After updating the information from this form, now my refund is less, so I owe $85.

What I should do? I should wait for IRS to notify me that I am missing a document (I do not know if they do that) or I should fill an amendment 1040X form?

I’d appreciate any help,