This potion is brewed from the sweat of torturous pain of virgin girls. Magical botox potion is injected directly to several spots on the face or other body parts what are wanted to look young again. Potion makes skin and body look like 18 years old and effect lasts for 2d6 weeks. After that skin is back to normal and user ages 1d4 years. That cannot be reversed.
If new botox potion is injected before the first wears out roll 2d6 again to determine new duration of effect. The effect is not cumulative but the aging effect is cumulative.
Player characters if using botox potion should not know how long the effect lasts and Referee should roll the duration in secret. It is high risk to use it as aging effect is immediate.
Eight full hours of continous torture is needed to brew one dose of this potion. In most parts it is highly illegal and criminal act and is usually done in secret. Rarely the method of creating botox potion is revealed to outsiders. One dose costs 1500 gp and is extremely rare as only few know the method and are morally low to do it.