Gets them off the planet quicker. Kind of obvious common sense..

I just think the events of all 3 seasons took a toll on him mentally and physically. Joyce and their relationship was just how that stress manifested. I really didn’t notice him acting differently. Everything felt organic... A lot has happened in a small amount of time. It affected all of the characters.

Problem is that cold sores are caused by the same virus as herpes. And no, 90% of people will not get them since you need the virus for them to manifest. That being said I don’t think her bath water is dangerous...