How often do you clean the tank now? my 1 gallons will only every go 3 days max before I clean it. Losing scales, isn't good, however it can be a sign of a sharp plant or ornament. Running pantyhose along plants, and if it runs you know your betta can get hurt by it.
Many skittish bettas end up with missing scales. and ripped fins too! Also, if he'd jumped out of the bowl before, scales can be lost just by being on a counter, or floor - clean or not!
It took one betta I had 3 weeks before he would eat, when I first got him. After he ate like no tomorrow. If you have minced garlic, take some of the juice with a spoon and soak some pellets in it. Bettas find it hard to resist it! Live foods, as well, which can be found in reptile, pet and/or fish stores. Frozen bloodworms, too.