I looked at the other topics on this first page of the forum and read the ones I thought might be related, but I didn't see anything similar to my betta's condition. I noticed yesterday morning for the first time what looks like his scales raised on his head where they are normally smooth (like his other scales). Aside from that he looked normal. I went to the pet store I normally go to and talked to one of the people working fish (I asked her if she actually knew anything about bettas and she said she has had them for a while) and I got some pimafix for fungus because I looked it up online as well and fungus matched the most. I didn't isolate him from his ten gallon tank because I don't have anything else to put him in and I wanted to try to save some money, but he's gotten worse since last night. His scales are more raised and the bumped up area has gotten a little bigger, and there are now white spots on the bumped area. No white spots anywhere else. There is a small white area on his underside right before his caudal fin starts. I noticed that a few days ago, but wasn't sure if I just hadn't noticed it before so I waited til it got better or I saw something else, which I did yesterday. I was wondering what else I should be doing to increase his chances of getting better.
temp- low 78 at night, high 80 during the day with the light on
ammonia tested 0 two days ago
chlorine, nitrates/nitrites tested 0 just now
alkalinity tested 40 ppm just now (a little low)
ph tested 7.2 just now
he has one tankmate, an upsidedown catfish that's only an 1 long right now that i introduced a week ago. he seems to be fine.
Any advice would be very appreciated!