Well not doing well

My water level falls down to the bottom of the well where the pump is, but never really quits pumping just slows down and the pressure gauge bounces from 10 to 20. My question is as long as water is around the pump will it eventually harm the pump, or can it just keep pumping like that alot?

The pump will probably overheat and if it has one, the thermal overload will shut off until it cools and then repeat that until the on'off cycling eventually kills the motor.