Loose pedal bent under pressure
Generally speaking, when a pedal works its way loose and is ridden for a decent amount of time, it does strip (and thus ruin) the crank arm. The only way you can be sure that the crank arm is good is to inspect it. So I'd guess your crank arm is damaged (especially if its at the point where you can't loosen the pedal). 

A picture of how its bent in would be helpful, but theres a decent chance that both parts will have to be written off.