I have just cleared up my betta's pop eye, and he was doing great. Back in his tank and was fine. I noticed him this morning looking funny. It looks like his head was swollen around the gill area. I took him back out and put him in my QT tank again. I am not sure what happened, but he I can definitely see his gill is swollen on one side and the scales are a bit raised. He is in a heated, non filtered gallon tank by himself. I am not sure if I need to use AQ salt, or epsom salt on this. I could use any suggestions you all have.
I attached a couple of photos. They aren't the best, but hopefully you can see what I am talking about.
Thank you for your time.