Wiper spline! help!

Basically my car froze over pretty bad last night, I started the car, heaters on full like you do... and my wipers tried to clear the screen (where I left them on from last time I was driving) only the driver side luckily snapped the clip to keep the blade on and I've now discovered that its rounded off the spline form which it sits on! so now it has no way of being timed... just wondering if anyone has experienced something like this? how did u make it work without replacing both the arm and studding!