Botox around the mouth lasts on average 3 months. This area is a very mobile area and often times very little Botox is used to prevent side effects. Side effects of too much Botox would be the inability to purse your lips around a fork or water bottle. Botox around the mouth helps improve the lines/wrinkles. Filler injected into the lip for augmentation lasts 6 months. Botox is less expensive around the mouth due to less of a dose. It can range from $100-$200. Fillers range from 500-$700 depending on your location.
Botox usually lasts about 4 months fillers can vary between 6-9 months for most hyaluronic acid fillers. Best of luck.