Xin Liao, Jingping Wu, Hongbin Cheng, Huilan Zheng, Ying Peng
Botulinum toxin has expanded beyond muscle paralysis to multi-target skin regulation, with growing interest in its use for post-acne erythema, atrophic scars, and enlarged pores. However, the quality of evidence varies widely. This article critically integrates the mechanisms and clinical evidence of intradermal microdroplet injection for treating post-acne sequelae. Botulinum toxin may inhibit inflammation, regulate sebum secretion, influence vasodilation/constriction, and modulate fibroblast function via the non-neuronal cholinergic system, providing multi-target theoretical support. The clinical evidence level is low to moderate for atrophic scars, with a focus on combination therapies (microneedling, lasers, radiofrequency, etc), but most do not quantify dermal penetration; thus, the specific contribution of botulinum toxin is uncertain. For post-acne erythema, only one small RCT and one case series exist, with low to moderate evidence. Enlarged pore studies rely on before-after or retrospective designs, with low to very low evidence. Computer modeling offers quantitative references for formulation conversion and parameter optimization, but its conclusions derive from glabellar or muscle-targeted data and require prospective validation for acne applications. In summary, botulinum toxin shows theoretical potential for post-acne sequelae, but the current evidence is weak. Clinical use should be limited to investigational settings or exploratory options after conventional treatment failure.