White "sore" on gums

I've had a white crater looking spot on my gums for over a month now. It doesn't hurt at all, not even to the touch, but will not go away. I have not started any new medications and have not been ill to my knowledge other than a cold. I've never had a cold sore (nor has my husband) and I don't think it's a canker sore. I've also never smoked or used tobacco products. Any idea what this might be or what I can do to clear it up? I've been using a peroxide based mouth wash for a few days, but it doesn't seem to be helping. Any thoughts would be appreciated; thanks!

[EmergencyMedicine]

A canker core is obviously the first suspect. Keep at the peroxide if its helping. Let me know how you feel. Get well soon.

[EmergencyMedicine]

Have you had any sort of injury to that area? Like did you bite on it by accident, or were you punctured by a dentist? Minor injuries can cause a sore of that sort.  

[melabooms]

No injuries or recent dental visits; thought it was possibly a canker sore from stress (quit my job, moved to another state, husband was deployed) but like I said there is no pain associated with it. I have restarted the peroxide rinse and it does appear to be getting better little by little...

[EmergencyMedicine]

A canker core is obviously the first suspect. Keep at the peroxide if its helping. Let me know how you feel. Get well soon.