1) Look in the mirror, and smile. Then say, "You can do it! I believe in you!'
2) Listen to your favorite music. Listening to your favorite music can keep you motivated. Most people that use music to reach their goals have a high chance of getting through. Music basically inspires you to keep pushing along.
3) Rewards. When you are trying to finish a task/goal the best thing to do is set up an reward for you earn for getting through. So when you finish your task/goal you can reward yourself with food/candy/or whatever you'd like.
These are some of the few way's to motivate yourself when it comes to every challenge.
I think that most nosebleeds will stop on their own after a fashion (D) but depending on the severity of the nose bleed then they should C- seek medical attention.