In my experience, people with buttocks herpes recurrences definitely can see distinctive lesions. They are in groups and are certainly blisters. Has your clinician evaluated for or treated you for a yeast infection? The burning, itching, redness is most often associated with genital yeast infections. Sometimes at our clinic, even if we don’t see yeast under the microscope, our patients get better when they try a round of anti fungal medicines in the vagina. Just a thought.
And yes, sometimes we do see pregnancy changing things in terms of herpes – the location of outbreaks or the severity or frequency.
I suppose you could talk to your provider about increasing your daily dose to 1000 mg to see if you can avoid those episodes. 1000 mg is actually the first approved dose for suppression and 500 mg is the alternate dose, though most people do perfectly well on 500 mg. If you still got those symptoms on 1000 mg a day (or 500 mg twice a day) then I would be less inclined to think these symptoms are herpes related.