Got a D in an online class- what's the damage?

Ok so first of all I know similar questions have been asked before but I’m freaking out her and need some direct reassurance.

Ok so I was accepted into BU ED and kept my grades up the following 2 semesters (my school does 4 semesters per year). Overall I think I did rather decently and did not have too many issues with senioritis. Until this quarter

I went on an exchange program for a few weeks in France and as a result my work for my online classes fell short, my AP psych class in particular.

I ended up not taking the exam bc I felt completely unprwpared and overwhelmed bc I had missed so much school and decided to focus on my other APs (which I know makes everything look even worse)

It’s an online program that’s self paced so I assumed I’d have more time to complete my work, but the class has closed and I don’t think I have any way to bring up my grade.

I know this is all my fault and I really messed up. I’m just wondering how badly I screwed myself? Will one D cause them to rescind my application even if I get high Bs and As for my other classes (which I know I will)? Or do you think I will just get put on academic probation or something?

I only post in this specific thread bc I’m not sure what specific policies BU has in place. I know it’s a case by case thing but I wonder if precedent will work in my favor or not.