You might want to have Neko tested for worms, even if any previous fecal was negative. You do get a false negative if the worms aren't shedding eggs when the test is run. You might want to read up on hooks; they are not something one wants to take casually.
Our first grey had hookworms for 9 months before the third fecal found them. Meanwhile, they had spread to the lungs, and he did that rapid cough-up-and-swallow-immediately thing that sounds so much like a reverse sneeze but itsn't. He also bit at his sides, though further back then in your photo, because hooks have teeth and bite. Thus he would also sometimes suddenly jump in the air for no apparent reason, as if he had been bitten. (I reported all this to the vets, but my state didn't have hookworm back then, so they weren't familiar with it and how it distinguishes behaviorally from other kinds of worms.) Though I haven't heard of it before, I'd guess hooks could be biting and drawing a little blood in the stomach that's showing up on the food when he coughs it up.