Rub on until it is absorbed. Putting a hot water bottle over the area will also speed the healing. Cayenne causes a topical burning feeling, but this goes away after a while. Cayenne is generally recognized as safe. Cayenne, when taken raw, is not caustic to the stomach, and has helped heal ulcers.
Cayenne is one of the purest stimulants.
And it is used as a catalyst in many formulas to speed the digestion and absorption of the other herbs in the formula. N.D. Medical Herbalism, Vol. I thought it would be easy, but it didn't turn out that way. When I get this figured out, I will link it up.