it's hard to tell from the pics (almost looks like the siphon). The last pic looks normal, but maybe that's just because it's the back of the eye.
I'm sorry you and your octo are dealing with this; I'm not sure if anyone has recommendations for treatment, but I can dig through our archives for injury care; it's certainly been discussed in our forums, broadly speaking. I know @robyn
has direct experience and has done research in anesthesia for cephs, etc, so it may be worth reviewing her posts/threads.