Oscar may be in trouble?

Hello! New here.
It has been 6 days since my Oscar has been having weird bubbles on his skin. On the first day, I thought it was ich so I turned up the heater to 86 degrees and added 1/4 tea spoon of sea salt and increased aeration to account for the increase of heat. I have also changed the water on the third day.
Should I add medicine or go with another approach to the situation?

I've added some pictures. The first picture was first day, the last two was taken yesterday.

Do you mean aquarium salt? As far as I know sea salt should not be used as medication in a freshwater aquarium. As far as the skin bubbles, I am not too sure. Maybe @Colin_T could help?

What is are your current water parameters and tank dimensions,? it looks like your tank is completely bare no substrate no plants rocks or wood unless this is a hospital tank I would add some natural surroundings

The fish is covered in excess mucous, which is normally caused by poor water quality or something in the water that is irritating the fish.

The air bubbles are sticking to the excess mucous.

The water looks cloudy.

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What is the ammonia, nitrite, nitrate and pH of the tank water?
What sort of filter is on the tank?
How often and how do you clean the filter?

How often do you do water changes and how much do you change?
Do you gravel clean the substrate (assuming there is some) when you do a water change?
Do you dechlorinate the new water before adding it to the tank?

Do you add any chemicals, fertilisers or anything else to the tank?

Did you add anything to the tank in the 2 weeks before this started?

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At this stage, I would test the water and then do a 75% water change every day for a week or until we work out what is going on.
Make sure any new water is free of chlorine/ chloramine before it's added to the tank.