Botulinum toxin slims the shoulder muscles by blocking the nerve-muscle junction, so that the muscles lose nerve nutrition and atrophy, in order to achieve the effect of slimming. The overall effect is more obvious, but it needs a certain onset of effect time, and the effect usually starts to appear about 1 month after injection. Under normal circumstances, there is little risk associated with Botox injections. However, there are certain risks if Botox is not injected properly. For example, it triggers muscle paralysis, which affects mobility and can induce muscle atrophy in severe cases. There may also be injection adverse reactions, such as local numbness, pain, swelling, redness and so on. Usually disappear on their own within a short period of time. There is also a possibility of infection if not sterilized properly. Once the infection occurs, it should be treated in time, and in rare cases of allergic reaction, epinephrine should be used for treatment. After injection of botulinum toxin, candidates need to pay attention to avoid strenuous exercise, because the drug will act on the muscle, this time strenuous exercise is easy to lead to muscle damage. Avoid water in the operated area for 12 hours after the operation, and if accidentally exposed to water, dry it immediately. Also need to prohibit hot compresses, cold compresses, compresses are not conducive to the slow diffusion of drugs in the muscle. Avoid taking aspirin, this drug is easy to cause bleeding, although the thin shoulder needle is very thin, the skin trauma is very small, but there is also the possibility of bleeding. If the shoulders are fat due to excess fat, the effect of shoulder injections will be greatly reduced, because Botox does not have an atrophic effect on fat.