Betta fin rot

[bettalover123]

My betta has had fin rot for a month now and nothing I'm doing seems to work. As a last resort I followed a youtube video to use seachem kanaplex and jungle fungus clear. So I had a question my bettas extremely stressed now and he refuses to be in the open water and he likes to hide is that normal for a sick fish? Also I'm guessing that my betta is cutting himself on the aquarium décor as its pretty rugged. Also does fin rot cause erratic swimming?

 

[fishwonder]

Here is help for Fin Rot. Good luck.