Herpes is by far the most
commonCommon cold overall cause of genital sores. Your description is pretty typical for recurrent genital herpes, but it is also consistent with a minor skin infection, like folliculitis or a pimple. If you have herpes, almost certainly you have had it from some past sex partner; nobody gets genital herpes from hand-genital contact. Such prolonged but previously asymptomatic genital herpes is very common, perhaps especially when the infection is due to HSV-1, which causes less frequent outbreaks than HSV-2.
Yes, you need to see a health care provider for proper diagnosis. Assuming all traces of the genital lesion are gone when you are examined, you'll need a blood test for HSV-1 and HSV-2. If positive for HSV-2, that will make the diagnosis firm: you have genital herpes. If negative to both HSV-1 and -2, it will prove your genital lesion was not due to herpes. If positive for only HSV-1, you won't know; that outcome could be due to either distant childhood oral infection or to more recent infection, either genital or oral.
Bottom line: I don't know whether or not you have genital herpes, but it's possible. If so, you didn't acquire it from your current manual-only girlfriend.
Best wishes-- HHH, MD