Red swollen meatus after masturbation

A few years ago, one night I was masturbating and on aproximing climax, a burning pain striked on the tip of my penis. I remember the days after, my urethra opening was red, swollen (the skin looks like lips) with urge to urinate (and no urine came out) and also a small burning feelling when peeing that I sometimes continue to feel today. The fake urge to urinate passed with time but the redness and swollen is still there.
I was virgin back with no sexual activity besides masturbation, so I think it's not STD.
I then went to my family doctor and he saw my penis and said that it was caused by friction and it was nothing to worry about, prescribing me Nupercainal cream. The cream helped with the redness and swollen when I used it for 1 month I think, but after I stopped using it, it return to the previous red and swollen state.
I went to another doctor who prescribed Hidalone Hidrocortisone and Sertopic antifungal cream. But it did not help.
I feel no pain in ejaculation, never had blood on urine/semen or discharge. Sex is normal, no pain associated. Just the damn redness and swollen urethra lips, and some burning sensation sometimes when urinating :confused:
I am now preventing myself from masturbation or sex to see if it makes a difference.

(I have some pics I took from my meatus, I can PM them if it makes a difference). Thanks.

Red swollen meatus after masturbation