Treating the entire skin at once would lead to a very long recovery with high risk for infection and complication (think intense chemical peels and fully ablative laser therapy)
If you've tried everything take your vet to the cat and also ask them about B12 How to Give Your Cat a B12 Shot Don't give your cat a B12 shot without consulting your vet first
Sources of vitamin B12 include: Animal sources of vitamin B12: Meat, including beef, lamb, and pork Fish Poultry Eggs Dairy products, including milk and cheese
If you use a sterile needle then there is no need to 'dunk it' in alcohol
The additional stability comes from the complete cessation of molecular mobility at these extreme temperatures
So are many drugs used in endocrinology, reproductive medicine, and oncology including leuprolide (prostate cancer), oxytocin (labor induction), and vasopressin analogues (diabetes insipidus)