How long does the effect of Botox for frown lines usually last?

Perhaps because I have a habit of frowning unconsciously, I have developed deep vertical wrinkles between my eyebrows. Since I look angry even when I'm not, which sometimes leads to misunderstandings, I am seriously considering getting Botox for the first time. I've heard that Botox is the fastest and most effective treatment for frown lines, so I'm curious how long the firmness lasts after just one injection. I would also like to know if there is a significant difference in the duration of the effects depending on whether I use a domestic or imported product. I am terrified of getting injections, so if you could let me know if it hurts a lot, it would be a great help in preparing myself mentally. I hope everyone has a relaxing weekend.