Botox is a drug made from a neurotoxin produced by the bacteria Clostridium botulinum called botulinum toxin. It is administered for cosmetic treatment as a very small number of units per injection site. Botox works by blocking the nerve signal to a muscle, so that the nerve continues to work but the muscle does not contract. Other products now include AbobotulinumtoxinA (Dysport), RimabotulinumToxinB (Myobloc) and IncobotulinumtoxinA (Xeomin).
These are not interchangeable, and injections are usually done in the doctor's office. If this live bacteria enters the bloodstream, it will attach to the muscles and replicate, weakening or completely immobilizing the muscle. In fact, this toxin is quite deadly. However, even if the needle is injected into a vein without knowing it, and the doctor does not realize that Botox is being administered intravascularly, there would be no expected adverse effect from such a small dose distributed over a wide area through the bloodstream.
Alarming new studies have revealed that paralyzing toxins within Botox can travel to other parts of the body. There have been reports of serious adverse reactions in people receiving Botox, and an analysis of the FDA database by Public Citizen found 16 deaths from Botox or Myobloc. The majority of these came from people who received Botox to erase their wrinkles, but 28 deaths occurred in people who had received it for medical purposes. I have also read some articles stating that Botox enters the brain, causing people to suffer from symptoms that create permanent disability.
However, one of the main reasons why Botox and its cousins were doing well was that preclinical tests showed that, after being injected, they did not travel along the nerve cells of the body's roads to the brain and spinal cord. With new evidence that Botox can spread to the brain in ways that preclinical tests failed to appear, it is enough to recover those expression lines erased with Botox. The Food and Drug Administration has launched a safety review in response to these reports. That's highly unlikely, but it's a more than compelling reason not to go bargain hunting for Botox. Consulting with a reputable and established injector is the one you would discuss your concerns and questions with to help educate you and inform you about the possible side effects of Botox injections. For example, a person is likely to experience no trouble breathing after being injected with Botox in the face.
When it comes to headaches, researchers have stumbled upon the effects of Botox on migraines. Botox injections block certain chemical signals from nerves, mainly signals that cause muscles to contract. Shelton's answer is for educational purposes only and is not intended to constitute medical advice. Information provided should not be relied upon as a substitute for consultations with a qualified health professional who may be familiar with your individual medical needs.