Disfigured faces later change to reflect a persons heart

Need help identifying a book, with only a 25 year old description from memory. Was after the apocalypse, only a few people remained on earth, but their faces was all disfigured. People became good and bad. Years later, unexpectedly, their disfigured faces hardened, then cracked to reveal a new face. Bad people were ugly while good people were beautiful. Can you help me with the name of the author and title of the book?

Swan Song by Robert McCammon

That book title has eluded me for 25 years. Thank you for your quick response and for giving me some closure.