What book series had a Dr. who was a false prophet?

I cant remember much about the book since i read it in a long time ago, but i do remember the titles of the two books from the series had March and April in them. And there was a contest about collecting all the months. The book had something to do with people melting and following a false prophet who claimed to be a doctor. The only quote i remember is him asking someone ';do you know what the Hippocratic Oath is'; then thoroughly explaining it before killing someone who defied him. I really want to finish this series because the two books i read where the most twisted from the doctor and romantic from a side story of two kids that i had ever read.What book series had a Dr. who was a false prophet?
Countdown by Daniel Parker.


I forgot his last name, but his first name was Harold.





Edit: Harold Wulf was his name.