Anyone heard of random bruises, the bruise that you get without even knowing, some chinese people said it's getting pinched by ghosts lol.
I don't get bruises that easily and if I do I would just leave it, but few years ago I would have used chinese oil (yerk yau) to rub it, if it's serious then boiled egg, crack the shell and then rub. The harder you rub the better as it promotes blood circulation.