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.
Neurotoxins are used to block the signals from the nerves to the muscles, which causes the muscles to relax temporarily. These neurotoxins 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.
Side effects of neurotoxin injections includes muscle weakness near where the medicine was injected, headache, tiredness, droopy eyebrow etc. It is important to have such injections done only by a qualified medical doctor. The effects of such injections will wear off slowly over the next few months.