I would continue to change at least 50% per day until wound appears to be healing. If wound looks at all infected, I would do 100% water changes. One of my females had a chunk taken out of her side by another female in sorority tank. I removed injured girl, Liv, to a glass water pitcher and am doing 100% water changes per day with stress coat and aquarium salt. If I had her in a 2.5g, I would do 50% water changes per day as there are no signs of infection.
I would remove the ornament as well. Perhaps you can add some live floating plants and something soft like cabomba...my bettas like to hide in the plants, it makes them less stressed.