It’s not TMI at all, and it’s great you can ask questions like this.
So look, this isn’t good. And if he were an experienced dom I’d be spitting teeth and telling you dispatch his ass out the airlock. But he’s not. It sounds like he’s just got carried away and doesn’t realise just how important safewords are to making any kinky stuff work and be safe and consensual.
So you need to sit him down, tell him how you’re feeling and absolutely do not let him shrug it off. You need to make it clear he is NEVER allowed to do that again, it’s a huge betrayal of trust and he needs to know how serious this is.
But if you can do that, and think he’s got it, then I encourage you to forgive him, and move on, and let it be a learning experience for you both.