shocked, doctor says sore on my labia looks like herpes...what?!

I am married 25 years and off and on have had pimples that raise up on labia or pubic bone, usually just one pimple.  Always thought they were ingrown hairs.  They are painful and last a week or more to heal.  Today my doctor says the active sore looks like herpes, he gave me a stupid smirk when I asked what else it could be, he said it did'nt look like an ingrown hair.  He told me next time I get a sore come in and he will culture it.  He did not culture the sore I had saying since it was 4-5 days old it would not be acurate?  My husband and I are freaked out about it.  If herpes how long could I have had this?  I've seen my husbands penis on a regular basis and he has NEVER had a sore.  So I believe this is all me.  I don't even know what to do or where to go to find out.  Isn't there a blood test?  I'm going to be freaked until I have another sore and that could be months....any advice?  Thank you.