I have dealt with early scale rot, what you did was correct. Add to the treatment is every day for 7-10 days I’d put a diluted drop of Bernadine on the troubled scales and rub it in and let it sit for ten minutes. Wash off with warm water. Pat dry. Then a tiny tiny bit of normal antibiotic first aid ointment and rub that on. Give it a week. Let shed, should be fine. If not, vet trip.