Oh, when you do the daily water changes, remember to re-dose the salt in the replacement water, just the amount that the replacement water needs, not the whole tank again. Eg: if you remove ten litres, replace ten litres and dissolve the salt in the 10 litres you're re-filling the tank with.
Salt is a brilliant treatment. It has anti-fungal, anti-bacterial, and anti-parasitic properties. That combined with fresh clean water is the best treatment for what your fish have been through
Salt and fresh water changes alone saved a guppy of mine that fell out of the tank when I took out the sponge filter and it tore her whole tail off. She started to develop fungus and I thought I might lose her, but she went from this;
to this;
And the salt killed off the fungus within a couple of days, and her tail showed regrowth within a week. So don't give up hope
a 50% water change might be enough, doing another dip test should tell you what your levels are now.