OMG! This happened to me Thursday left and a couple of months ago too! Nothing ever came of it but like you it's driving my crazy as to what it could be! I'm sorry I don't have an answer for you but I'm interested also if anyone else has had that or knows what it is! Thanks....
Does sound like a cold sore though i have had one before once and also had the tingling but never a cold sore so you will have to wait and see. If it does come out get some blisteze on it every couple of hours will soon go.
I get this sometimes,and within 5mins,I get a little lump like a blister,on my top lip.It generally disappears within 10 mins or so,and it might happen about twice a year,or less even.Have no idea what also what it is,and I don't get cold sores either.