My question concerns the so called Mephisto effect from an injection with Botox.

The Mephisto sign and its closely related cousins, the dreaded Spock and Jack Nicholson look, are related to placement of Botox within the large muscle on the forehead called the frontalis. With misplacement, a portion of this muscle is not immobilized properly, which allows different forces to be placed on the brow, altering the brow shape. This does not, however, change the overall amount of force that this muscle is able to put on the brow that would "stretch it out," and actually decreases the overall force, reducing wrinkles in the long term. If there is a shape change in the brow, it can be  corrected with a subsequent touch up treatment by a skilled injector. 

To ensure you are receiving the highest level of care, seek out a modernly trained, new-school dermatologic surgeon, oculoplastic surgeon, facial plastic surgeon or plastic surgeon who is board certified and fellowship trained in one of these "core four" cosmetic specialties.

Cameron Chesnut#realself500 Physician

Good question. Botox does not stretch skin. However, when giving Botox for migraines, the eyebrow can drop, giving more upper eyelid fullness. This should be discussed as a consequence of migraine relief with Botox. Frequently, we perform upper blepharoplasty to eliminate the fullness.