What are the potential risks associated with injecting botulinum toxin too close to the marionette line safety zone?

Injecting botulinum toxin too close to the marionette line safety zone can lead to lip asymmetry, cheek flaccidity, or oral incompetence. These complications arise from affecting nearby muscles like the depressor labii inferioris, buccinator, or orbicularis oris.

Injecting botulinum toxin outside the marionette line safety zone can result in several complications due to unintended muscle involvement. If the toxin affects the depressor labii inferioris muscle, it can cause lip asymmetry by altering the central lip's position. Lateral injections affecting the buccinator muscle may lead to cheek flaccidity, impacting mastication and increasing the risk of cheek biting. Additionally, injecting too close to the lip could involve the orbicularis oris muscle, leading to oral incompetence, which manifests as drooling or difficulties with speech, eating, and drinking. These effects are generally temporary, resolving as the toxin's effects diminish over time.