by TnT!
Hmm. The card reads:Spend 2e at any time to heal 1 damage
So, I would interpret that to mean, yes you could spend more to heal more.
Spend 4e, then heal 2 damage. Spend 6e, heal 3 damage. Etc.
The key is "at any time" - essentially you activate the card multiple times. And since it is a keep card, spend away...
This is in the FAQ.
http://boardgamegeek.com/thread/743476/faq-in-english-answer...
However, you cannot heal if you are dead. I think.
If you have 3 life left, you could heal immediately before the attack. But once the attack is made, it must be resolved before you can heal.
So, if you had 3 life and 4 energy, but took 3 damage, you'd be dead. Too late to heal after the damage is dealt. I think.