I still have a dent in my thigh from a spill I took five and a half years ago. I'm not sure whether it was the hematoma itself that caused it, or whether both the hematoma and the dent were caused by damage to the connective tissue that happened in the impact.

I think heat and gentle self massage help (both by increasing blood flow and by gently breaking up the clots so they can be absorbed). If you happen to have an electrical stimulation unit, those have been really helpful to me over the years in working out all kinds of swelling, but I probably wouldn't apply the pads over scabs or even newly healed skin.