Welcome and good for you starting to parasite cleanse.
I have NEVER had a parasite come out alive. If you don't look in the toilet you won't even notice any parasites that come out.
No they are not painful when they exit your body. I have never had a live one come out of any place on my body.
I think you will be fine, I was scared at first too. Come here for help and to ask questions, we will try to help you, heyjude