I've been getting forehead botox consistently for about 5 years, but recently, it's all gone in less than 3 months, and I feel like I have wrinkles ㅠㅠ I used to get it for more than 6 months... Is it because I've built up a tolerance? And the price difference seems to be big depending on the dermatologist... I wonder if the maintenance period is different depending on the injection.