For steaming very small areas like that, I heat a small piece of flat steel with a torch, and hold a wet paper towel on the dent, then press the heated steel onto it (mind you, don't heat it to glowing, just hot enough to burn you). It will create a concentrated burst of steam - your best chance of removing the dent. I've brought out some serious dents using this method, and the rest get finished into the gun as patina. You may still have to refinish that area to a degree.
-Eric