Presumed cut in urethra - stinging pain when urinating

For context, I am a 20 year old otherwise healthy male. For the past week I've been experiencing a stinging pain when I urinate. The pain doesn't happen until my urine reaches the tip/meatus and it is extremely painful. I have been tested for STDs/STIs and yielded all negative results. I also initially was treated for a UTI and my doctor called me confirming that I didn't have one because there was no bacteria in the urine sample. The other night I lifted up both sides of my urethral tip and found there to be a red spot/cut from which all of the pain is presumably coming from. I have no pain when pressing on my shaft or pelvis - only when I press on the head of my penis, and specifically the side that this redness is on. I have uploaded pictures to imgur and will link them below. I have no idea how this happened and did not feel it when it did. https://imgur.com/a/U77vl54 https://imgur.com/a/Xc7l3aW Is this a cut or something more serious? If it's a cut, how will it heal? I have a urologist appointment Tuesday but it's very painful and I would love answers sooner than later.

it resemblss herpes.

have you seen something similar to this? that really freaks me out

you need to have a culture swab done.

swab came back negative. symptoms subsided after a week of doxycycline and valacylocvir (i was prescribed it in the chance i did have herpes).

im having trouble believing the swab because the symptoms subsided exactly 11 days after they started and i feel like that would make sense to be an initial outbreak. i didnt have any other textbook symptoms like no lymph node swelling or fever ect.

what are your thoughts? could i have swabbed too late? should i just believe it and move on with my life? i plan on getting blood tested in a few months when antibodies would be there