How do you get a cold sore i have a bump on the top of my lip but it's not yellow or red it don't have 3 little lumps ?

Variable: Cold sores are painful liquid filled blisters that can occur on the lips, roof of the mouth or the gums which are usually caused by the herpes simplex virus (HSV-1). Tingling &/or pain can herald the oncoming of cold sore 1 to 2 days prior to eruption.

Cold sores: are caused by the herpes simplex virus. You can see your doctor to see if these bumps are cold sores or something else.