To have best control with where you steam, use a soldering iron instead of a regular iron.
Here's a technique that often works, sometimes not, sometimes only just adequately. Take on of the clear wax fill sticks, use a burn in knife to melt it into your dpression/dent. Take a flat adge razor blade - the painters' blade, not a utility knife blade. Wrap a piece of masking tape on the top, this will be your "handle". Heat it up with a flame. Use this hot blade to scrape your wax fill level. Dust on Mohawk's clear satin precat. Wait for it to flash and dust on more, do this a few times. Lightly scuff with a Scotch-Brite.
Another method to level a wax fill is to take a piece of copy machine paper and wrap it around a hard, flat (really flat with no bumps) block. Before you do this paper/block step try to get the wax fill as level as possible. Use a razor bladfe or the edge of a credit card. Note: to use the credit card edge you hold the plastic at a shallow angle to the surface (an oblique angle) and you move the card in small concentric circles to "sneak up" on the edge of the fill, or else there's a tendency to pull the fill out. Then, with the paper wrapped tightly to the block, rub over the fill, press somewhat hard. The idea is to create friction to heat the fill. Last step, again, Mohawk aerosol precat satin sheen, dust it on.
Why satin sheen for a flat sheen surface? If you use flat or dead flat, even if the sheen might read the same when measured with a sheenmeter, it shows up flat -- too flat - from some viewing angles. You want a blend in, not a spot spray that says, "Look at me."