You are correct in that the Assessment Mark/Grade reflects your internal performance in a particular subject (in this case, Physics). Essentially, NESA offers HSC results services, but while this is the case, none of these services apply to the Assessment Mark. Instead, they target HSC exams; for instance, the HSC Results Check provides students who believe that an Examination Mark is not consistent with their expectation with the opportunity to confirm that their mark was processed correctly, after which their Examination Mark either remains the same or is corrected. An increase in the student's ATAR may also follow as a result. This service therefore targets the Examination Mark, which is not helpful in your case.
As much as I sympathise with your situation, I doubt that you can do much to change your Assessment Mark at this stage. This is because your Assessment Mark has already been determined based on the assumption that you were fully aware of your rank and that not informing your teacher that it is incorrect implies that you are satisfied with it and believe that it is correct. NESA states that you should immediately speak to your teacher if you believe that your rank is incorrect, which was possible for you once NESA made your ranks available and thus constitutes grounds for not changing your Assessment Mark.
The only possibility of being treated as an exception is in the event that you were not informed in any way that you would gain access to your ranks in your subjects after the HSC exams, in which case this would not be a fault of yours. If this is what happened, it would be a good idea to contact NESA to see whether something can be done to rectify this issue.
All the best!