Is it my pedals or my crank arm thingy?

[Oysterboyz]

I have a question....I kinda ripped out my pedal yesterday on a ride and I thought it had just become unthreaded but when I tried to put it back in, the pedal didn't fit into the crank arm anymore. So did I completely wear it out on the pedal or on the crank? What would I have to do if it's the crank arm that's also got threads that were ripped out? Would I need a new set or just replace the arm?

(I'm hoping that it's just the pedal then I can just get new ones...)