The biggest thing is, when you fall, try to NOT use your hands to catch yourself. This might be kind of hard to learn, but if you lose your board and you are going to smash into the ground, you should try and let your shoulder and body take it, rolling with the blow as much as you can. Catching yourself with your hand is a great way to break a wrist, and while wearing wrist guards can protect you from this, it's dangerous to get used to using your hands, because at some point you will skate without the wrist guards ...
So, those times you do get hurt, what do you do about it? The best thing to do is to get up if you can, walk around and shake it off. Every time you fall, your body will learn to avoid doing that again. You shouldn't get hurt too badly from skateboarding, but broken bones are pretty common. If you think you've broken a bone or hurt something bad, get it checked out. You'll hate yourself if you find out a month later you were hurt badly, but the wound healed wrong and now things are twice as bad. If you see a doctor, take the doctor's advice! Wounds heal, and you'll be fine in no time. After you're better, the most important thing of all is for you to get back on your board, and keep skating.
