Assuming that you don't have a deferral, you should have your "card" in hand when you leave the doctor's office.
This.
But if your "in error" submission contained something something that would cause you to be deferred, I'll counsel you to make 100% sure that you know you will pass before going live with the AME. If you are less than 100% sure, get sure by consulting with the AME (aka he looks at you and your paperwork, but does not turn in the code) to find out what info and documentation you need to bring to be issued.
If you actually do have something that prevents him from issuing in the office (such as a condition that requires a Special Issuance or SI), your exam will be deferred so that the folks at FAA-Medical in Oklahoma City can review your case. This is where knowing in advance what they want and formatting it so the low levels can approve is very important. If all of the documentation is there and the low levels can say "yup, he meets the standard", then you should see your medical in about 45-60 days.
But if you bomb into the office with a condition that requires deferral and your submission packet is incomplete or poorly organized, then you may encounter a major delay while OKC says "We need this additional data, and you have a short deadline to send it in." And even if you send it in immediately, you're back at the end of the line for your case to be reviewed. And hopefully you won't get another "We need additional data" letter and get further behind.
Again, all of that can be saved by knowing all there is to know about your current health condition and that you meet the FAA standards for issuance BEFORE you enter the AME's office.
And if you don't have any health issues that require deferral, then you will be issued your medical certificate before you leave the office.
BTW, the latest Guide for Aviation Medical Examiners can be found at
this link.