Everyone can repent, even the vilest of sinners. Pedophilia is an addiction and a sin. As a sin, it causes guilt and sadness to compel you to repent. Pedophilia is not a mental illness as the world would say. At one time, you were most likely a victim. This doesn't excuse your sin, but the knowledge does help you understand that you need healing along your journey of repentance.
Repentance only comes through Jesus Christ. No one else can substitute His power. Repentance breaks down to two actions: confess and forsake (see Doctrine and Covenants 58: 43).
You need to confess to the proper authorities, your victims, and your church leader. Your church leader and God will help you know what is the best way to confess to victims. Understand others will react strongly. Confess every instance to the authorities and your church leader. This is like cleaning a wound--all of the infection must be gone before the wound can heal properly. Be willing to suffer the consequences and spiritual pain.
Forsake the sin for the rest of your life. This process is difficult, but worth it. This includes making restitution where possible. Just like an alcoholic should avoid a bar, you need to avoid tempting situations. Importantly, prevention is key. Here are some prevention tips I have thought of:
1. Be completely honest with yourself and others.
2. Avoid children and places children go. Never be alone with a child.
3. Keep a person as your "line of sight." This person should not be any person who will hide the truth from you or others.
4. Inform others so they can help you avoid being alone with a child.
5. Pray and study scriptures often.
6. Avoid pornography in all forms and other sexual sin.
7. Seek professional help from someone who will be honest with you.
8. Be aware if you notice yourself grooming a child (e.g. giving candy, attention, or toys)
9. If you sin again, repent immediately!
This will be a lifelong process. Call on others who are willing to help you along your journey. Rely on the Lord because He loves you. He is the only person who can redeem you.