I've been detoxing off and on along with a preventative program for 5 years. (I'm 65) I've done several parasite cleanses and have never had anything that hurt. Perhaps a mild headache once in a while. Drinking a lot of water and enemas help to get any toxins out more quickly.
Younger people are less likely to have the fecal build-up in the intestines that older people sometimes have... that is where parasites like to live. You might want to do a Colon Cleanse first.
Although it happens, I don't think 'scattering' of parasites is common.
I work at making an un-welcome envirement for parasites by eating a healthy diet.