Unless they are fungused or infected keeping his water extra clean for a while will help his fins heal. You may even have to do an extra water change each week for a while. Sometimes the medication we must use to help them can be hard on them in other ways. So you really don't want to use another medication this soon if you don't have to.
I'd been changing water thrice a week since I ended the first treatment with the E.M. tablets, just to promote health. AND because pleco poop gets wrapped around things sometimes and it gets on my nerves. They were small changes, probably 15% or so. I've used Stress Coat and Stress Zyme for every water change. I'd hoped it would help this fish's fins, but they look like they're just become more and more ragged.
So I started treating with Maracyn II since I found it today. I went into Petco for brine shrimp, came out with arms loaded down, as always. I'd been looking for both Maracyns for a while now, so we'll see how that goes.
Off-topic, I also got a small tank for the bettas. Since one died, I'm putting the other two in the same 2.5 gallon tank with a divider and filtration. They've been in bowls since the summer began! Probably since April or May, even. I espied a 40 gallon that I may or may not go back to get. If not that, then definitely a 29 or 30.