It is worth noting that a number of the Church Fathers, particularly the monastics, did in fact hold that wet dreams are a sin. I think their position has been discredited by theology, but it’s still worth noting. They are certainly irritating, and they are a reminder that, however good you are, you are still bound up by what St. Augustine called the “glue of lust”.
But, no, nocturnal emissions are not generally held to be something that you need to bring to confession. I certainly haven’t. It might possibly be a sign that there are other problems in your waking life, such as a tendency to lust, and that’s worth considering in your next examination of conscience. But it’s more likely that it’s totally beyond your control, so don’t worry about it. I’ve had dreams where I was a murderer, but all it meant was I was feeling a little stressed out in real life, not that I was really just as bad as a murderer.
And, like StephenFrancis says, the vast majority of young men have done (or habitually do) deliberate masturbation while awake, even when they know it’s wrong and they want to stop. So say a prayer of thanks to God that you’re not in that situation, and don’t beat yourself up over a very small, questionably problematic thing.