Should u change toothbrushes after every herpes oral outbreak?

HSV infection, mouth: Herpes simplex virus 1 & 2 do not survive outside their host for more than a few seconds. It would be rare for you to infect yourself with your own toothbrush. I presume you are not sharing it with someone else within seconds of an outbreak. So you are not at risk of rue infecting yourself with your own toothbrush. You should change it periodically anyway, like every 3 months.

Not that necessary: Cold sores/herpes are quite common and can be contagious. Changing your tooth brush every 3 months or so is recommended for dental care, but not that necessary for cold sore prevention (assuming u r not sharing toothbrush). The virus that is causing your recurrent sores comes from your own body/nerve, not toothbrush. There are medicines to suppress them if you have frequent recurrences. Good luck.