The average Botox injection lasts three months, says Joel Schlessigner, M.D., an Omaha-based dermatologist and plastic surgeon who uses Botox, Dysport and Xeomin to treat those dreaded facial furrows. "These treatments need ongoing maintenance," he says. "The face returns to close its original look in most people, but with some benefits that last. The nicest benefit is when a frowning person is 'retrained' not to frown," he says, explaining that some patients conscientiously avoiding frowning or furrowing the brow as much after treatment. “Some people hold their face in a habitual way and Botox can interrupt this pattern and force them out of the furrow, allowing the face to resume a more natural look.” He adds that patients should return every three months to maintain the frown-free look.