Put a dab of water on the affected area. Not too much. Just enough to cover the dent(s).
Cover it with your paper towel/rag. At this point, the water will wick through the material. That’s fine.
Now, with your iron on its highest setting, hold it over the affected area and make small movements back and forth and in circles. Press down firmly and continue until your paper towel is dry. It won’t take long to evaporate.
At this point, the wood fibers are absorbing the water and should expand back to where they were originally.
Continue this process and repeat by adding more water until the dents rise up to be flush with the rest of the material.