Many patients with symptoms of CRPS in the face comment on changes in facial appearance associated with decrease pain following treatment with ketamine

Other examples of changes in facial appearance:

...   Escalating Dose Patients

...   Ketamine Coma Research Subjects

Associated with improvement in facial appearance show in the above photos, the patient reported decrease in pain of the face and an improvement in mood. The improvement in pain is evident in the pain thresholds below.