
Titles aren't as important as covers, true, as they don't often, on their own, "sell" a book. But they are still of value. Just like font style, the image and idea that a title conjures must be one that encourages a reader to choose your book over any of the multitude of others.
Third degree burns do not serve that purpose. Being "touched by fire" isn't sexy or appealing. Rather, it sounds frightening and painful, and you'd probably be better off choosing a title that's a little less... flamey.
Unless your book is actually about a burn victim in a burn ward. In which case, carry on.
Touched by Fire -- Gwyneth Atlee