The first pic you can clearly tell that it is rot. I have had this with many motoro imports. They pull through if you do what mike suggests. I didn't go as high as 90, more like 86, and daily 50% w/c's. and used Melafix. The first sign of winning that I notice is the whiteness subsides and the disc edge starts to reform/scar over.
Is the underside slough and indication as well?
Can you isolate him?