Frown lines are creases between the eyebrows that can form or become more pronounced through repeated activity of certain facial muscles. Their depth and pattern vary from person to person. They are not a reliable indication of someone's mood.
Botulinum toxin treatment can temporarily reduce muscle activity. Established lines respond differently. Possible side effects include bruising, asymmetry and temporary drooping of an eyelid or eyebrow.
Headaches and migraine are separate medical conditions. They should not be attributed solely to visible frown lines. Their assessment and treatment must be distinguished from purely aesthetic wrinkle treatment.