Herpes Or Trauma? Single Red Flat Lesion On Shaft

I went on vacation for 2 weeks, did not masterbate or anything of the sort for that whole time and also showers were few and far between. When I got home I masterbated vigorously, 4 - 5 times throughout one day, dry with no lube or lotion. On the last go around I noticed a small a very dull sting, immediately checking only what looked to be a very tiny skin graze (as if skin was rubbed off) or cut on the under shaft of the penis, no redness, only a bit tender when messed with but virtually painless when left alone.

Day 2: Naturally I take a look at it, it's a bit red now with more of a mild "irritation" pain only when touched or squeezed, but still painless when left alone. At this point I started applying Triple Antibiotic ointment twice daily and keeping a band-aid around it. Also looked a bit swollen / slightly raised at times, while still being so small that to fully inspect it required good lighting and the skin to be stretched.

Day 3: after still applying triple antibiotic ointment and keeping a band aid on it, peeling it back it looked as if any "swelling" or raising had subsided. It now looks like a tiny rug burn, again as if the skin had been rubbed off. Any tenderness and pain was so little that I had thought it had disappeared within the day. Hardly tender when touched.

*I have not been sexually active for about 8 months now, all sex was protected except for oral, and with my girlfriend at the time.*

Main Question: Could this be an STD? Or trauma from a lot of masterbation at one time? Doing a lot of online research has freaked me out to think I might have herpes, but a lot of my symptoms don't seem to fall under the common symptoms of a first outbreak. I have an appointment at planned parenthood but unfortunately it's booked out pretty far.