Unfortunately, there is a risk of getting a heavy eyebrow when the horizontal forehead wrinkles are treated overzealously with Botox. To understand why this happens, we must understand how the vertical and horizontal forehead lines are formed, when they occur with expression.
Vertical “11” lines are caused by the depressor muscles (which pull the eyebrows down and inwards) and the horizontal lines when you raise your eyebrows are caused by the frontalis muscle which acts to pull the eyebrows up and outwards.
It follows that for a good balanced result with Botox treatment, one has to accept a trade-off between the depressors and elevator action. Trying to “freeze” all the horizontal lines in the forehead with Botox will inevitably cause inability to raise the brows. Often this will be noted by patients as being unable to apply their eye makeup or mascara without manually lifting their eyebrows using a finger.
During consultation for Botox treatment, experienced injectors will ask you details of how your previous treatments with Botox or other botulinum toxin such as Azzalure went, did you have any side effects, heavy brows, droopy lids. This is important to understand how you respond and tailor a good Botox treatment for you.