It won't 'hurt' the trailer not using it, but proper weight distribution will help create a balanced tow vehicle and potentially provide a safer ride.
The setup for various weight-distribution hitches is different, so if you can find a manual for yours, or get one online, that's a great place to start. Without access to a scale, most instructions are going to have you aiming to have a very slight drop on the rear suspension with the bars properly tensioned.
There are lots of variables... if the tongue weight of your trailer isn't very high, you might not need weight distribution at all. The possible way to damage a trailer with a weight distribution hitch is to put so much torque on the bars that the resulting load on the trailer damages the suspension or makes the trailer ride so hard it gets wrecked.
I tow a 22 foot with a tongue weight of <> 400lbs, and loaded weight around 4500lbs. The extra weight of the WD hitch is self-defeating for me. I was looking at moving to a 25' which would be <> 800lbs on the hitch, and would be pretty sketchy with my current tow vehicle without weight distribution.