I have balanitis, but i am wondering whether it is fungal or bacterial. how can i tell which it is? is either of them life-threatening?

It's usually not possible to know fungal versus bacterial versus "nonspecific" balanitis. The main health effect occurs if restricted foreskin (phimosis) prevents foreskin retraction. It's never life-threatening. Usually clears up with foreskin retraction and washing with soap and water a couple times a day. If that doesn't work, try an OTC yeast cream. If still no relief, see your doctor.