I'm only a novice, but this happened to me years ago on a Sea Doo. First of all you turned the jet ski back over in the wrong direction. But you probably already know this.
When this happened to me, I also had water in my cylinders. I removed the plugs and turned over the engine - water came out the plugs holes. I left the plugs out and left it in the sun and put fans directing into the plug holes for around 24 hours. It was difficult to dry out the cylinders, but I eventually did. Put the plugs back in and keep trying to fire it up. Hope this helps.