muggie

Hi All n hope all ok, need some advice and expert opinion please folks.. i have an 02 316 and a mile from home the cam shaft sensor failed but managed to limp home in safe mode i think they call it, i have managed to replace the sensor but had a mechanic out to reset box and clear fault code but now as it wont start he telling me i have bent the valves n rods... need a new engine... is this correct or could it just be something electrical?? please help lol ... Lee