Vitamin B12 Injections Boost Energy & Wellness in Frankfort Causes and Relief Tips for a Swollen Arm After a Flu Shot Has anyone had a b12 injection and told to stand up while doing and not all inserted and some went down my arm xx Some people think the needle is left in their arm when they have IV. In reality, it's only a small plastic catheter that is easily bendable. So don't be afraid to move Feeling worse after B12 Injection: Answering concerns. La Vie Med Spa