I thought had tackled fin rot for my betta in early Dec. But I've hardly seen any new growth. People said to wait but it's been long enough. I had done salt water baths and a treatment of polyguard. That was the best I could do at the time.

I put her in her hospital tank (3g), with the intention of just having salt in the aquarium for about a week. But then, I noticed her gill and need help because idk what it is 😳 

She normally is in a 15g fluval flex with plants, driftwood, a small piece of cuttlebone and the water tests fine. I do regular 20-30% water changes weekly. N03 is never above 20. Ph 6.6 everything else 0. The only other issue I had was BBA, but I have that under control. I did recently get new moss two snails and added them to the tank. An assassin snail and nerite snail. The moss is 1 2 Grow, so it was sealed. I glued it on driftwood and the little hut I have in the tank. Besides the betta and 2 snails, I have 4 guppies and 3 ottos. 

I'm not sure how long she had this and I'm freaking out. I've googled and chat gpt'd it but I get mixed answers. 

Can anyone help me by identifying what is wrong with her gill? Will it spread? Is there anything else I can do? Am I doing the right thing? 

Honestly I was just going to put her in the hospital tank with aquarium salt but I added the kanaplex today. I really hope I'm doing this right, so any advice I would appreciate! Thank you in advance! 

I'm doing my best here. Please don't be mean! I'm honestly here for advice for what's best her and will do anything! 

Does anyone know what's wrong with my betta's gill?