Botox in Forehead - I've been applying witch hazel to these spots but why have I reacted like this?

I had Botox about just about 8 days ago and I have small pimple like spots in the injection site. The nurse likes to use a fresh needle for each injection site so used about 6 needles and all were sterile and in packaging. There was no cross contamination. I've been applying witch hazel to these spots but why have I reacted like this? Incidentally I'm very pleased with the result. This was the first time I've had Botox I'm just a bit miffed about having these red pimples. Thanks for any advice