I think i have a cold sore developing on my upper lip. does this mean i have herpes?

Possibly: It is true that some cold sores on the lips are a form of herpes called herpes simplex type 1. This does not mean that you have genital herpes. Herpes viruses are common and many people get cold sores. If they are frequent then there are medications that your doctor can prescribe treat this type of herpes.

Cold sores: commonly caused by the cold sore virus HSV-1,which is a herpes virus but rarely sexually related.