I have been caring for a betta that was ill and now seems to be doing better for a month or so. Today I was showing the tail regrowth to my roomate so held up a mirror to get him to flair. Thats when I noticed something strange. When Bettas normally flair, the skin under their gills comes out to make them look bigger. on Miroku, this extra skin only came down on one side, though his gills opened on both sides. Is this permanent damage from when he was sick or somethig that might improve? Is there something i need to do about it?