Also, the proper temperatures in the cage should help also...you mentioned "keeping him warm now", I hope he eats for you...they typically do take pinkies OK.
If he was cold before when you offered, that alone could have caused his refusal. When you keep snakes in captivity & allow them to get cold, they instinctively
may assume it's time to hibernate & stop eating for the season; for this reason, it's always best to set up the cage ahead of time, before putting a snake in it.