How does olive oil help heal bruises, and prevent knots and tumors?

As a kid I used to fall down alot and bruise myself, my mother would rub olive oil on the bruises. Later when I asked her why she said that our family has a history of developing knots and binine tumors from bruises and this is a way to help heal them after massaging it into the skin. I never had a chance to ask her why it worked... do you know why?

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