Complications — About 25 percent of people have chest pain for a few hours after the procedure and about 5 percent develop heartburn. Damage to the esophageal wall and lining are rare. The short-term safety of botulinum toxin injection is greater than the short-term safety of both balloon dilation and surgery; this greater short-term safety may make botulinum toxin injection a better choice for patients with other serious medical conditions (eg, advanced age, severe heart or lung problems) who cannot tolerate a balloon dilation or myotomy.