I've started Mr Bevo on Melafix and extra aquarium salt for the time being. I'm learning this fin rot stuff is mighty persistent sometimes, now from experience and reading the experiences of others online.
I sent off for a betta medicine kit from Faith at http://www.bettatalk.com/ She carries some meds that can't be found in regular stores especially the gram negative antibiotics. I contracted to have a phone consultation with her several years ago and found to her to be a most warm, bright and knowledgeable individual. Some betta keepers recommend the Melafix/salt cure so we'll try that for now and see what happens. The antibacterial properties of the Melafix should at least keep him in a holding pattern until the meds arrive in the mail. If worse comes to worse, I can do another consultation with the bettatalk lady on the phone. It's basically a non-fatal disease if it gets treated.
Other than that, he's speeding around his tank zig-zagging up and down so seems happy and active. He could eat 24/7 so I have to resist overfeeding him. He's so sweet about coming up to the surface to feed practically right from my hand. He's so cute, it's hard not to spoil him!!
Further updates are forthcoming about the fin rot situation....
The photo is of Faith and her band Alternative Faith.