"面部的歪扭" can be translated into English as "facial distortion" or "facial contortion", depending on the context and degree of severity.
"Facial distortion" is a more general and commonly used term, referring to any abnormal or misshapen appearance of the face.
"Facial contortion" emphasizes a more extreme or intentional twisting or deformation of the facial features, often seen in expressions of pain, extreme emotion, or certain physical conditions.
In most everyday contexts, "facial distortion" would be the more appropriate choice.