Raise the damaged ceiling tile off of the support rails surrounding it, then turn the tile and remove it from the ceiling.
Place the tile on a flat work surface where you can easily see the damage that needs to be repaired. Because the metal is thin, the most likely problem you will run into is that the surface is dented in. If this is the case, turn the tile over so that its decorative side faces down.
Hold the metalworking dolly against the underside of the dent. This will prevent you from damaging the metal by bending it too far the wrong way.
Strike the underside of the dent with the flat head of the metalworking hammer. If you need to repair the raised design of the panel, use the pointed end of the hammer to refashion the metal into its correct shape.
Appraise the repair by placing the tile flat on the work surface again. If you cannot see appreciable damage to the tile, and it does not appear to be warped or otherwise damaged, replace the metal tile back into the ceiling.