Good questions! Herbal medications are just like any other drugs - an X amount of herbs can only kill an X amount of beasties. You did feel better and will continue to feel better. Do try adding the "in-between" herbs to your daily diet. They WILL help.
Yes - do another round of HUMAWORM in 90 days. Just a regular strength will do fine. Then, if need be - do another one after that in 90 days. I have some customers who cleanse every 90 days - while others only cleanse 2 times per year. More than this is overkill and can create resistant parasites.
Some people just like to liver flush as an added measure - it will literally flush out any remaining dead parasites and toxins from the liver. It is not necessary - but it dosen't hurt a thing if one chooses to do it.