Sorry, I wasn’t able to find much of anything on the ‘net about this. I’m going to guess that it might not be anything too serious, but on the other hand, blood flow to the penis is important for maintaining erectile function, so it’s prbly a good thing you’re getting it checked out.
Since you said it’s not getting any worse, I don’t think you have too much to worry about as far as ‘waiting too long’. If I were in your shoes, I’d just wait until I could see the Dr. If the Dr. isn’t able to answer your Q to your satisfaction, then you should see a Urologist, who’s prbly going to be much more familiar w/ unusual cases like this.
Good luck to you & please check back in after the Dr. app’t & let us know what he/she says...