My son who is 7 has had botox about 6 or 7 times since he was 2 1/2. It worked really well when he was younger. The first couple times it lasted close to a year each time. He first only needed it in his calves, but as he has gotten older, he has had his hamstrings and adductors done. It usually takes close to a week to see the best results and he has a little trouble with being too lose for a few weeks until those weak muscles get built back up.
Now, it will work really well for about 3 to 6 months depending on much we stretch him and how active he is.
When they are doing the shots, they are painful. We have never put him under because of the risk and how quick a procedure it is. Last time he was
stuck about 10 times I believe. It is hard to watch, but I won't let him go through it without me in there. His physiatrist has a service dog that she has used in the past that really helped calm him.
We feel that the botox is a better option at this time than the orthopedic surgeries that he would need otherwise. He will need surgeries in the future, but we are hoping to delay them as long as possible.
Good luck with the botox.