Compare tail rot to MRSA.
Just because you get a cut on your knee, doesn't mean you will develop some flesh eating bacterial infection. Just because your dragon injures it's tail, doesn't mean it will develop tail rot.
Tail rot is exceptionally rare. In fact I can't even recal the last time we actually had a case of what I'd consider true tail rot here. And we see hundreds of dragons a month come through this forum.
The closest is what happened here:
viewtopic.php?f=45&t=249975&start=30#p1906184
And that was just an accident from the dragons tail touching the nebulizer. The tail got damaged enough that it died, but it didn't develop tail rot, it simply died and fell off. Of course the OP had kept the tail clean and sterile. The tail has recently just broken off at the injury point. Of course, technically, the tip of the tail that dies is in a sense rotting I guess you could say, but it's a natural process that their bodies can handle typically. And tail rot isn't really that serious unless and infection sets in.
There is a lot of misinformation out there in regards to tail rot, and thanks to a couple popular articles, a lot of unnecessary fear has been caused. Unless the tail is looking worse than the tail in the thread I linked, there is a good chance it's not actually anything serious.
Remember, the tail can get damaged, can even die in an area and fall off, all without tail rot being involved. Tail rot is a serious infection in the tissue of the tail that eats it from the inside out basically. As long as you keep the wound clean if it's open, there should be no issue.
Anyways, I'm rambling a bit but it's like looking at Webmd when you are sick. You usually read the worst and it typically is nothing to even worry about to begin with
Since their was an injury though, it would be best to keep it sterile and clean until it's healed over. Raw unpasteurized honey does great for this. Just don't leave insects in the tank. Or you can continue the iodine treatment if you'd like.
-Brandon