Rear Derailleur/Mech Hanger problems

Today I noticed something was bashing into my frame/cassette area when I rode over bumps. So stopped to take a look and realised the rear derailleur wasn't in the position it should have been in. So after some inspection I found this to be the problem:

I believe this is one of the limit screws, I'm not quite sure how this has happened as it was fine yesterday when I rode the bike. I am going to take it to the lbs tomorrow, will it just need the screw replacing, or the whole derailleur? Or could there be damaged to the mech hanger?
Tried to get the screw out myself, but my stupid multi-tool managed to censored up the screw head.

I believe this is one of the limit screws, I'm not quite sure how this has happened as it was fine yesterday when I rode the bike. I am going to take it to the lbs tomorrow, will it just need the screw replacing, or the whole derailleur? Or could there be damaged to the mech hanger?
Tried to get the screw out myself, but my stupid multi-tool managed to censored up the screw head.
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get a new screw.
Parktools :?:SheldonBrown
I am intrigued as to how this actually happened, I haven't done anything at all on my bike that should cause something to break like this :?
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Hmmm maybe, I would have thought I would have noticed if that happened though, whatever it was that smacked into it would have had to have been pretty close to my leg as well!
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