Looks like white veins. Need help!

[mypleco]

I went on vacation. Told my father to feed him daily. When I returned he looked like this. What is it? I already tried Melafix and I think it looks a little better. His fin is also messed up im guessing he been fighting with the other pleco. Never has happened. He doesn’t move when I tap the glass and he stays im one place outside now he doesn’t even hide. Any help please