The Question and Answer section for Dr. Jekyll and Mr. Hyde is a great resource to ask questions, find answers, and discuss the novel.
It becomes apparent that Jekyll and Lanyon had a falling out when Lanyon refuses to speak of Jekyll and doesn't even want to hear his name.
Yes, the conflict in this story is an internal one. Dr. Jekyll transforms himself into Mr. Hyde and is able to indulge in all the bad things he keeps buried inside of him. Soon the lure of this double life gets harder and harder to break....
Hyde used Jekyll's checkbook to pay off the parents.