How long does a black and blue take to heal?

I have a few black and blue bruises. They started showing blue and sensitivity within less than 24 hours. How long will it take to heal?


I bruise really easily. Sometimes I can go to cross my legs, hit my knee lightly on my desk and the black and blue is still there a couple weeks later. Sometimes I get a black and blue harder and it lasts shorter. And will putting neosporin on the bruises help?


Thanks.|||It takes about a 5-7 days.