"She would have known that when a willing victim who had committed no treachery was killed in a traitors stead, the Table would crack and Death itself would start working backwards. And now-"
"Oh yes. Now?" said Lucy jumping up and clapping her hand.
"Oh, children," said the Lion "I feel my strength coming back to me. Oh, children, catch me if you can!" He stood for a second, his eyes very bright, his limbs quivering, lashing his tail.
So i thought that when he said that death itself would work backwards that he would get younger. Also he seemed more lively after, which brought me to think that perhaps Aslan was getting younger.
On the other hand he said that Death would work backwards i thought that perhaps he would just come back to life.