The first time I discovered PIED and really got into rebooting (the first time around anyway), I reluctantly went to the doctor after a tough conversation with my wife (to this day she does not know PIED is the true issue). It was hard, there is no doubt about it, but I bit the bullet and put it out there with him at the tail end of my next appointment which was about another issue . I don't know what I expected, but it was fine. They are doctors, they aren't going to laugh or judge. He just asked me a few questions, prescribed me a 30 day supply of Cialis (which to date I have not needed to use though I have considered it), and that was that. I didn't get into the porn stuff with him, I just told him what had been happening with trouble getting and maintaining erections. I told him I didn't think I really had a physical ED type problem, but the few times I had a problem had given me performance anxiety which was more of an issue than anything physical. He told me that sometimes using something like Viagra or Cialis to have one or two 'successful' sexual encounters can give you the confidence boost you need to not need them again. If he had asked me about masturbation or porn or anything, I would have been 100% honest. He just didn't ask, so I didn't get into it. He also did a blood workup to see if I had low T or something like that, and the nurse that called me with my results said that everything was normal.
I am older than you, 36, but the way I really approached it was I KNEW it wasn't a physical thing with me, it was all mental and I knew it was due to my porn/PMO habits. I just wouldn't admit it to myself, but the act of going to the doctor and having to discuss it was very humbling and got me into rebooting hardcore. I ended up falling off the wagon and restarting a few times before being off for about a year and PMO'ing almost every day. Now I'm back and better than ever and two weeks clean from porn and masturbation and I'm feeling great.