I know this isn't quite the advice you're looking for but - in case it helps - in my experience, arnica gel (available at any homeopathic shop) makes bruises disappear in half the time. That's not what the scientific literature says. Spanking safely is important - if you are new please read FAQ before spanking. Choosing your implement depends on how, why, and from what position you are spanking. Different implements will vary in sting, residual pain, bruising, and accuracy. It is usually best to have a variety of implements, allowing for a wide variety of spankings and effects.
As a general recommendation, we advise against any rubbing of the buttocks immediately after a spanking. However, if marks/bruises result from the spanking, we feel this would be an exception to that recommendation. There are fewer ways that wont leave any marks at all, but many methods make marks that fade after an hour or two and that dont affect the bottom's ability to do basic everyday activities. Spanking with an open hand on the lower ass amd thighs causes mild to moderate pain and leaves the skin red, which often fades after an hour or so.
Taking the Noise Out of Spanking by Matt Anglen From time to time we're asked about how spanking can be done more quietly, so that neighbors, kids, or visiting parents aren't perfectly aware of your activities. With a huge variety of toys at my disposal and numerous opportunities to experiment, I've come up with a few suggestions. Spanking is an art. In fact, the position of your hand and the way you hold it can make a big difference. You want to slap her good, but you also want to change up your techniques to make it a little more fun.