The disease can severely disfigure victims and cause death.

VOA: special.2009.10.14

To disfigure the mouth -- this is how I would interpret it -- to disfigure the mouth has a primary effect in rendering one at least temporarily speechless.

把嘴巴丑化--这就是我所理解的-,丑化自己的嘴巴使自己暂时不能说话,它是有十分重要影响的。

耶鲁公开课 - 弥尔顿课程节选