Hi, I am 35 yrs old and never had a blister or cold sore in my life. Well that changed today, I noticed 2 tiny blisters on my middle upper lip but it is where the mouth closes you cant see it but I know its there. What causes that, I consistently wash my hands, I dont drink after anyone, or been around someone with it, or contact. I don t know if there could be any type of connection but I had a horrible headache lasting 2 days, and the heat have been crazy...could that be the cause?