I accidentally dropped a small plastic part inside my microwave from the small openings up

i accidentally dropped a small plastic part inside my microwave from the small openings up and I can't manage to get it out.Please tell me if its dangerous to use the microwave or no like this.

It depends on a lot of unknowns. A microwave has moving parts like fans and gears to turn the dish. It just depends on where the piece landed. It's not dangerous to use it as long as the plastic can't get blown into the food cavity and into the food but you risk doing serious damage to the appliance if the plastic landed in the wrong place inside.

I would take the cover off and remove it. Obviously you don't do that with it plugged in and make sure everything gets put back exactly as it was. A microwave can be very dangerous if the energy gets out of the box.