Do not iron a crease into the lapel. A well-made lapel should naturally roll without a hard crease by virtue of its construction. If you have a good tailor, they should be able to restore the lapel to its proper shape. If not, try the following link: http://putthison.com/post/9000329145/a-beautiful-lapel-roll-is-a-sight-to-behold-one
It is funny how a well made(?) jacket is not naturally rolling. It is maintaining the original crease.