Intramuscular injection of the neurotoxin complex blocks cholinergic transport at the neuromuscular junction by preventing the release of acetylcholine. The nerve endings of the neuromuscular junction no longer respond to nerve impulses and secretion of the chemo transmitter is prevented (chemical denervation). Re-establishment of impulse transmission is by newly formed nerve endings and motor end plates. Clinical evidence suggests that BOTOX reduces pain and neurogenic inflammation and elevates cutaneous heat pain thresholds in a capsaicin induced trigeminal sensitization model. Recovery after intramuscular injection takes place normally within 12 weeks of injection as nerve terminals sprout and reconnect with the endplates, as Cited on Electronic Medicines Compendium (EMC)