Had a ct of the lungs and they injected the fluids inside my iv that's makes you get really warm everywhere. when do the side effects wear off?

Almost immediately: Contrast material, or x-ray dye, is often injected IV in a ct scan to see things better. Some people 'feel' the dye as a warm sensation which lasts during the injection and subsides almost immediately. Some people have dye 'allergies' which usually manifest within seconds to minutes after the injection. They can be minor or more serious. Minor reactions include nausea, vomiting and hives.