Naw, I think normally Jake has that kind of dark hair that lightens in the sun and for indoor shots, esp the hospital scene his hair was slicked down and very tame, so probably whatever product they used just made his hair look glossy and darker by comparison when it normally just kinda goes all over the place.
Hello there lovely Jake-people... I'm here to make sure you all know about the birthday chat that's been organized for Jake's b-day on Dec. 19! Hope to see you all there!