The frons is most popular botox treatment. A frown arises because the muscles between your eyebrows contract. During the treatment, the front wrinkle is injected with botulinum toxin. This relaxes the muscles and makes the frown lines softer, smoother and therefore less visible. If the frown wrinkle does not disappear, a filler can be injected into the wrinkle after 2 weeks to soften it even more.