Can you help identify this book title?

I’m looking for the title of a book I read approximately 15-20 years ago.

It takes place in the future (mid 2000’s) with a war between the U.S. and Japan if I remember correctly. The Japanese have developed a weapon that instead of killing causes its victims to return to an infant like state. The lead character is facially disfigured due to a disease he caught while serving years before the war in South Africa. And he likes to whistle. The book also features a lot of helicopters.

Hopefully someone can help. If I remember anymore details I will post them here.

War in 2020. I love that book!

Hot damn! I was talking to a coworker about this book and couldn’t remember it’s name. It was driving me crazy! Thanks so much!