This trial aims to test the safety and effectiveness of Dysport® in preventing episodic migraines. Dysport® is injected into muscles to stop pain-causing chemicals in the brain. The study focuses on people with fewer than 15 headache days per month. Participants will undergo various assessments over a period of more than a year. Botulinum toxin type-A has demonstrated good efficacy in several studies of patients with migraine, although data from some trials have been conflicting.