Everytime you smile, frown or raise your eyebrows, muscular contractions in your facial muscles create creases on your skin. After many years of this, these creases and wrinkles can become deeper and more lingering. Eventually, they become visible even when your face is at rest.
Botulinum toxin is a protein produced by a bacterium called clostridium botulinum. Botulinum toxins block the signals from the nerves to the muscles, which causes the muscles to relax temporarily. It have been used in aesthetic medicine to reduce the appearance of undesired expression lines.
The toxin is injected into the face and blocks the signals that usually cause the muscle to contract. This gives the usual muscles that cause wrinkles the chance to smoothen out, returning your skin to looking smooth. This can also prevent the formation of more permanent wrinkles.
Common side effect of botulinum toxin injection includes muscle weakness near where the medicine was injected, headache, tiredness, drooping eyebrow etc. It is important to have botulinum toxin injection done only by a qualified medical doctor. In any case, if it happens, the result will not be permanent as the effect of botulinum toxin will wear off slowly over the next few months.