Unfortunately, the scales sticking out is a major symptom of internal bacterial diseases (the symptom's called dropsy and is the result of fluid accumulation due to organ failure).
At this stage, it probably can't be cured and I honestly would suggest euthanasia if/when it stops eating (if it has dropsy, it'll stop eating very soon). The best method is using a few drops of clove oil. Put the fish in a cup of tank water, add the clove oil (which is sold in most pharmacies for toothache) and the fish should drift into sleep. Add some extra clove oil to ensure its unconscious and then leave it in the cup for at least half an hour (more is better to avoid revival). Then dispose of the fish (DON'T FLUSH!).
Like I said, wait and see if it stops eating and I'd like to see a picture first. Also, if you have a spare cycled tank (or use mature filter media for an instant cycle), you can attempt to isolate the fish and treat it with antibiotics. However, this usualy has no effect besides stressing the fish. I personaly would give it a shot anyway - just in case the fish still stands some chance of survival - but its not worth treating the whole tank as you risk a re-cycle that could wipe out the rest of your fish and bring no benefits to the gourami anyway.