On August 31st, with two children, we went to my friend's birthday par…

On August 31st, with two children, we went to my friend's birthday party. The older one played by himself, the younger one she held in her hands for a short time, then I found out from her a few days later that they had lice and she found a couple of them on her daughter and also on herself. From us they couldn't catch them. We don't go to the garden, nobody comes to us. They love going to guests and the mother-in-law lives with them, works in the garden, and after a week, periodically itches my head. Maybe this is self-hypnosis? Please tell me if we caught lice immediately, would it be clear or do they need