For the past 3 years or so, every few months I get this sore on the roof of my mouth, on the hard part. It doesn't really match the pictures of a canker sore. It starts as a reddish-yellow area about 1-cm across, irregular in shape and bumpy and feels rough to my tongue. Usually about the same place. After a day or so it opens and is yellow, like an ulcer, with a red border. It typically heals in 10-14 days. I already have HSV-1 on my lower lip, but I haven't had an outbreak there in years (have had the infection for 25+ years). I'm not certain if this is herpes or not due to two things:
1) I should have an immunity from my many years of it on my lip. These sores have only started relatively recently. I get a comprehensive STD panel run every year and I've not shown a positive result for HSV-2, just HSV-1. I thought once you were infected and develop immunity, you couldn't get new outbreak areas.
2) It's painless. When it first starts there might be a very slight sensation. Not a tingle, more like an itch maybe. But unlike my outbreaks on my lips, it never gets painful. I've never heard of herpes being painless. Can it be painless inside the mouth?
The online information about herpes on the roof of the mouth is pretty scant. I am hoping someone here has more information. I'd go see my dentist but he's on vacation.