It will not cause it damage, but you may want to dial it back down to stock voltages/clock if you do not need the extra performance increase. This will increase it's lifespan(which will probably be longer then needed even at this rate of usage). I would worry more about it using extra electricity and heating up the room it is in. If you live in a colder environment you might want to turn the heat off xD.
Its OCed to 4.2ghz @ stock voltages. Is it necessary to put it back to 3.8ghz turbo?