HELP! Oscar sick

[bettalife]

So my oscar has a bunch of this mucus stuff on his body. Someone said that It was excess slim. He has hlle but it is healing up pretty well. But my main concern is he is pooping white and won't eat. I think that he has internal parasites. I added aquarium salt and raised the temp to 80 degrees. What should I do now? Thanks

 

[bettalife]

This is how he looks right now.
But I haven't seen him eat in almost three days please help me.

 

[bettalife]

Update
RIP little guy ):