I had a large water blisters on my lower inner thigh. I just woke one morning and it appeared. It looked as if I had burned my self. At first it was just 4 small fluid-filled vesicles and it itched a bit, but within 2 hours it formed into one giant water blister. It no longer itched but it was painful if my skin pulled or if I leaned on it. I couldn't sit normally. It was at least an inch and half in diameter. I went to my doctor to get it popped because I have to work and it was so big that I wouldn't be able to wear pants. She said it was a "herpes cold sore" and she took a sample of the fluid to get it tested. I won't be hearing the results for sometime, but I wanted to know if it's common for herpes outbreaks to become so enlarged? I've been looking at pictures and all of the pictures of herpes look like small red dots or little clusters of water blisters. My "outbreak" was so massive, I'm wondering if you think it could be herpes. I have had unprotected sex but he's never had a cold sore before and neither have I.

Certainly, herpes lesions can appear on the thigh - the same nerve group supplies the thigh that supplies the genitals.  Have you ever had a genital water blister or sore? 

But it could also be something else, something bacterial perhaps.  But it does sound concerning for herpes from your description, I must say.  However, your emphasis on the large size of it is curious.  

It is important that you call your doctor's office tomorrow and ask that if the swab test is positive, that it be typed (HSV 1 or HSV 2).  This is important in knowing about sexual activity in the future.  If this is herpes, and she was able to get fluid from a blister, then the swab test should be positive if it was handled correctly.  Do you know if the swab test she did was a culture or a PCR type test? 

Just be sure to ask for typing.  Sometimes, this happens automatically, but not always.  It will save you lots of steps if the culture is positive AND typed. 

I doubt that it will take that long for results to come back.  Will you please let me know and we can talk about it more?

Terri