I agree with Bill on this one, but would also add some of what Jeff Clark says too.
However, I'd change some of the order;
1. using acetone and a dropper, put just a couple of drops directly into the dings and wait a few minutes. This will remove oils from that part of the leather.
2.Then with some saddle soap and a toothbrush, scrub out the dings. This will clean dirt out of that part of the leather
3. Make a 25/75 solution of windshield washer solution and water, and drip that into the ding and wait an hour or two. This will soften the leather quite a lot and get moisture deep down into the area, but dry hard.
4. Then go with Bill's idea but instead of an iron, use a soldering iron held on top of the cloth, with the tip right in the ding. This will cause the leather to swell due to the moisture deep in the leather.
5. Repeat applications of the soldering iron for steam until the leather is proud to the handle. Let dry, sand down the area to be smooth with the handle. (Same as you'd do with repairing a dent in a car body.
6. Apply proper finish to the handle.
Stitchawl