Does CMU/UVA require me to self report the scores I got on my AP exam?

Short Answer:

No. You do not have to self report any AP score to Carnegie Mellon or University of Virginia.

You can decide for yourself which of your AP scores you wish to report on the common app when you apply to both those schools.

I hope that answers your question.

No colleges or universities will require you to send all your AP scores, part of the appeal of taking the exam is that even if you don't do well, sending scores is completely optional. If you have a 3 or above, especially on a difficult exam, though, you should consider sending your score. However, you didn't mention the exam you took or your score. Although it sucks to not get the score you wanted, hopefully, this will be a helpful experience for studying and taking AP classes in the future! My best regards!