Exaggerated lower frontalis and glabella after Botox injection

Botox is well known to be safe and effective; however, in some rare instances, there are unwanted side effects that every clinician should be aware of and can address to their clients. A rare encounter in the upper face is mild ptosis of the forehead along with mid-horizontal line that divided and parted the forehead into two distinctive nearly equal horizontal portions. A woman experienced a deep furrow line across her forehead post-Azzalure injection by a week, with noticeable glabella projection. This line should expect to resolve by itself within few weeks. This could be attributed to overactivity and overcompensation of the surrounding untreated muscles in the same vicinity. Also, it could be attributed to different forehead muscle patterns.