Not itchy and not painful doesn't sound like HSV; It's consistent with syphilis (although that doesn't mean you have syphilis).
I would suggest you get it looked at by a professional. If they get a good look while it's still there, there's a better chance for quick diagnosis.
Good luck.
can hsv rash developed after 1 month of receiving oral sex ? my rash is not itchy , no pain and no blister . just slightly raised .