2004 Fiat Punto Engine Revs without touching Pedals

Noises problem
2004 Fiat Punto V8 Front Wheel Drive Manual

hi i have a 2004 1.2L fiat punto and i just changed the timing belt and the head gasket and now when i start the car the engine over revs and wont go down can you help me? as i am afraid to drive my car.and i have tried everything

thanks