No It Can Be A Canker Sore But To Be Safe Get A Herpes Test. They Have To Test It While The Blister Is Fresh. Dont Touch It And Keep Your Hands Clean Wash Them Alot To Avoid Spreading Just In Case. If Its Hsv 1 Then You Will Only Have 1 Out Break And It Goes Away But If Its Hsv 2 Thats Genital. Getting Tested Is The Only Way To Know For Sure.