Treatment of Facial Flaccidity and Sagging after Botulinum Toxin A Injection into the Masseter

Plast Reconstr Surg. 2023 Mar 1;151(3):521-525. doi: 10.1097/PRS.0000000000009909. Epub 2022 Nov 19.


Background: Botulinum toxin A injection for masseter reduction is generally considered minimally invasive, safe, and effective. However, this approach may lead to facial flaccidity and sagging, especially in older patients with reduced elasticity of the skin and the soft tissue.

Methods: The authors analyzed 27 cases of patients who presented with the above complications and treated them with botulinum toxin A injections into the platysma and the depressor anguli oris muscle. The efficacy of treatment was evaluated by both patients and physicians.

Results: Ninety-six percent of patients were satisfied with the treatment outcome. One patient considered the treatment outcome unsatisfactory because of the lack of significant improvement in nasolabial folds. Physician evaluation suggests significant improvement in all patients, including the one who considered the treatment outcome unsatisfactory.

Conclusion: Botulinum toxin A injection into the platysma and the depressor anguli oris muscles is a safe, convenient, and effect treatment to correct the complication of facial flaccidity and sagging after masseter reduction.

Clinical question/level of evidence: Therapeutic, IV.

MeSH terms

  • Aged
  • Botulinum Toxins, Type A*
  • Facial Muscles
  • Humans
  • Injections, Intramuscular
  • Masseter Muscle
  • Nasolabial Fold
  • Neuromuscular Agents*
  • Treatment Outcome


  • Botulinum Toxins, Type A
  • Neuromuscular Agents