Wasn't trying to be critical but it's a contest. You take good pictures, just not a good subject fish. Stress lines are from being kept in bad conditions either from before you got her or after. They can only be removed with proper care. If they are uncomfortable in their surroundings or the water isn't above 76 degrees they will stripe up like that. I have a beautiful big Blue Devil Halfmoon male that stripes up like a girl everytime I change his water and it takes several hours for him to get his color back. Some females are just more timid than others and are more apt to stripe up.
It might be the bubbler that is stressing her out. Or maybe the heat changes lately. I am trying to get it right. Over 76 degrees feels really hot. I had my tank at like 73 and it felt too hot so I cooled it down. My temp is going up and down because I don't really know what to leave it at.
73 is deffinately too cold and if you lowered the temperature that would really make her stress. I have over a thousand Bettas in my bedroom and use a space heater to keep the room at 76 to 80 degrees. I had to add a smaller second heater to keep up this winter. Last year my room got down to below 70 for a day and a half and a few Bettas got velvet disease. It was very easy for me to treat and cure but I was lucky it warmed up outside to above the teens and they weren't cold for longer .