The effect of botulinum toxin generally lasts for 4~6 months, and the next injection is needed for almost 4~6 months. From the action principle of botulinum toxin, the effect of botulinum toxin injection appears slowly, and it begins to appear about 1 to 2 weeks after injection, and the effect reaches its peak in 1-2 months, and then the efficacy and effect gradually decline, usually after 4 to 6 months, and the effect gradually disappears, so the treatment of botulinum toxin is phased and reversible.