Tokina 100 f/2.8 Macro Repair Advice

[badpeony]

So, I'm absolutely mortified to admit that I dropped my Tokina 100 f/2.8 Macro. The focus ring is grinding and very hard to turn in manual focus mode. In auto you hear the motor trying to do its thing but nothing happens. I took a few shots in manual and they actually turned out great to the point I'm convinced smacking the ground helped with vibration reduction.

Are there things I can check myself for solutions? I've never had to have repair work done and am not finding much in the way of info or recommendations so any advice is appreciated!

Thanks!

Allison