WOAH OP 
This card does not suck nearly enough to have that effect
Eternity abuse anyone?
That could be an issue, but given the high startup cost involved, I'm not sure it will be as OP as you may think.
Consider: Eternity costs 6
, this costs 4
, thats as much as a dragon + an extra card to get it rolling.
Then consider the combo cost: eternity skill costs 2
, this costs another 4
... thats 6
each heal
So in the long run you have:
10
+ 2 card advantage startup
6
+ 1 card advantage per heal
At very best, this card is giving you 25 hp worth of healing.
Now consider the alternatives:
Flown adrenal staff - 3 card + 5
+ 1
for 20 hp per turn with no upkeep
Heal - 1 card + 3
for 20 hp (one shot)
Empathic bond: 5
+ 1 card for up to 23 hp per turn with no upkeep (but requires lots of creatures)
Lastly, consider the effect of timing...
At a cost of 10
+ 6
upkeep, this is at best a mid, if not late game combo.
Unfortunately, the chances of drawing more of these goes up with each passing turn. So more than likely, you will have to spend a LOT of effort to get and keep all your copies rewound in order to see maximal benefit.
Now, you COULD combo it with mitosis or fractal and eternity and EVENTUALLY you would ramp up healing to very very high levels... That would take an awful lot of work though. Quite frankly, if someone can pull that off consistently without being outrushed, then they deserve the wins.
