It is well-established that botulinum toxin (BT) injections improve quality of life in patients with postparalytic hemifacial spasm. Nevertheless, injection-related pain and contracture-related pain have not yet been studied. The primary objective of our study was to evaluate injection-related pain in patients with facial palsy sequelae, and to compare the standard technique (syringe) with the Juvapen device. The secondary objective was to evaluate the improvement of contracture-related pain one month after BT injection. We conducted an observational, prospective, monocentric study based on 60 patients with facial palsy sequelae who received BT injections in our university ENT (ear, nose throat) department. There were 30 patients in the Juvapen group (J) and 30 in the standard technique group (ST). All patients completed Numerical Rating Scale (NRS) questionnaires immediately after the injections and one month later. The average NRS score was 1.33/10 with Juvapen and 2.24/10 with the standard technique ( = 0.0058; Z = 2.75). In patients with contracture-related pain, the average NRS score was 3.53 before BT injection, and 0.41 one month after BT injection ( = 0.0001). Juvapen is a less-painful injection technique than the standard one. BT reduces contracture-related pain one month after injection.