Kerrie, welcome. Cute female betta there. Assuming you do weekly water changes, have a means to measure water parameters and you keep your nitrates as low as possible, what do you feed your betta?
I kept a sorority of 5-6 female bettas in my planted community 55g tank at one time. Loved them. A family favorite for sure. The problem was, over the course of a year or two, I lost them one by one due to bloat like yours is starting to display. The only thing I could attribute it to was the fact that they would eat too much, given I was trying to feed them along with a variety of fish who all eat at different rates in this tank. If I ever keep them again, it will be a sorority by themselves in a planted 20g long or the likes.
I would keep up on your water changes and feed very little and only 2-3x per week to see if things improve.