How can i fix my clutch?

Foolishly i let me one of my friends sit in my car (peugeot 205, H reg 5 door 1.4petrol) whilst i went to the rest room at a service station. When i came back, he was revving the engine, flashing the lights and blowing the horn at this group of boy-racers. He was seriously revving the engine. When i got back in the car it was really hard, if not impossible to put the car into gear. Is this anything to do with revving of the engine? I know very little about cars but i fail to see how revving the engine could have affected the clutch to this extent. Is it due to this revving or is it due to something else completely aside from this? The clutch was being pushed in at the time and was not in gear. I really hope you can help.