The department I am applying to doesn't explicitly require a resume (and doesn't even recommend it), but there is an item named "resume" in the "supplemental material" dropdown menu which I have overlooked. I realized that I didn't upload the resume only after the application has been submitted. I have contacted the admission office, but the auto-response says "We cannot update submitted applications with new SOP or CV or other information."
There is some information in my resume which isn't mentioned in the SOP, e.g. my experience as a teaching assistant. While I have requested a professor from my home university to include the TA experience in his recommendation (because I am his TA), it is said that most institutions in the U.S. don't read letters from Chinese professors. Besides, I suppose a resume serves a nice overview of my previous preparation, so I feel like the absence of a resume is going to hurt the probability I get admitted. On the other hand, there must be some reasons why the resume is made optional, unlike most institutions.
Should I be concerned? Is there anything I can do at this point?