CB will only regrade scores of 1 and 2 this year.
Just don’t send scores that you don’t want schools to see. For very top schools, send 5s, don’t send 3s, and while 4s are often a discussion topic, I’d send them.
And fwiw, several top schools don’t look at APs at all in admissions, and no one puts significant weight on them. What you did over a year-long course (i.e. the grade on your transcript) is much more important than a single 2-3 hour test.
This is just another data point supporting the “self-studying for AP exams is a bad idea” advice regularly given here.