Once you've got split ends, there's actually no way to get rid of them without cutting them. It sucks, but just trim your hair regularly. It'll still grow nice and long, don't worry. My hair grows slow as hell and I trim it regularly, it actually seems like it's growing faster now! But here are some tips to prevent split ends: shampoo every other day, deep condition your hair weekly, never brush it while it's wet, avoid using heat (curler, flatiron, blow dryer), don't rub your hair really hard to dry it, and don't tie pony tails too tightly.
Coconut oil is primarily a moisturizer. You could take a drop or two, morning and night, and rub it into your face as a moisturizer. You could also use it for your body, though the biggest use is really for your hair (in my opinion). It's probably best to just put it in the ends of your hair, because if it gets into your roots it could potentially clog them or just cause a lot of excess oil.