Once again, I reiterate: YOU ONLY NEED B-12 INJECTIONS IF YOUR SERUM B-12 LEVELS ARE LOW OR IF YOU HAVE PERNICIOUS ANEMIA.
B-12 injections do NOT raise your white blood cells unless you are B-12 deficient and have a pancytopenia/megaloblastic anemia from lack of B-12. If you have a leukopenia, it is either drug-induced, heridatary, or acquired, and the underlying cause should be sought.