I struggled with this too. My first Confession a few months ago after about 6 years of no confession, where I had baiscally abandoned the Church was quite “embarassing”. It took me a good few months to write everything down, and get up the nerve to go. I knew I had to do it in order to be in full communion with the Church, after having left it for so long. I literally wrote a list of everything that I could remember that I had done, with the “bad stuff” up first, so I could just put it out there. It was such a humbling experience, and awesome to hear the Priest say “Welcome back home”.
I also MADE myself do face to face. I figured I had done the sins, and I needed to say them outloud to the Priest, as if I was staring Jesus in the face and telling Him all I had done wrong. Not to say anything negative about screened confessions, but for me…I wanted to stare at what I had done in the face, so to speak.Sorry, I am getting off of the subject, but I think you can say to the Priest “you know, my last confession was incomplete, and I want to say ___ sin.” There’s nothing that this Priest hasn’t heard before, and he won’t judge you, he is there to allow Jesus’ forgiveness and healing, and to wipe sin. Go for it, you’ll be so happy and humbled that you did!