Yeaaaaaa! Your 'kraut looks very good. We make a small crock of 'kraut about every 4 months and I don't think it would hurt anything if you stir the discolored stuff into the rest of the cabbage. It's all good. Many folks would want to remove it though. It looks like you have chopped the cabbage into tiny pieces, please let us know how you like it. Did you do that with a food processor? I usually shred the cabbage into one to two inch long slivers.
GOOD JOB . . . I think I can smell it from here.