@Ai9964 I'm getting the impression that Yuuki staged it. The wound was made with Akane's nails, and you have to deliberately sharpen your nails a lot for them to draw blood with just an accidental swing.
That wound being exactly on her face, where you can evade something like that easier, and "conveniently" the cameras not recording them making up (which to the internet, doesn't exist)...
It's all too convenient for her. And I think that Aqua noticed it too.