I actually disagree Viva. I know for a long time that I also advocated for salt to be used before medications but upon further research I'm finding that medications are much less stressful than they used to be. Sure 5-10 years ago and more, medications were much more harsh than AQ salt so that's why it was always suggested to use it before medications but since then, we've really stepped up with medications and now they are much less stressful!
Honestly the only thing that AQ salt does is agitate the slime coat and balance out electrolytes which, yes, that is good but it doesn't do much for advancing fin rot. If it actually is more fin rot then I would suggest to start the use of Erythromycine or BettaFix even, KanaPlex is great as well, basically any antibiotic.
Erythromycine will treat more of the gram negative bacteria (which I find mostly is fin rot I believe) and some gram positive, while Tetracycline will treat more gram positive and some gram negative. So if you find that Erythromycine doesn't work, you can use the Tetracycline instead. It's similar to combining Maracyn I & II which you can also use for Fin rot.
Keep in mind though, the more you use a medication the less it will be effective later in life, generally. This isn't always the case but it does and can happen