Idea is good of course. Stats... could be tweaked.
The difference between unupped and upped version is pretty huge. With these type of creatures, HP is maybe more important than attack. You dont bring such creature for damage, you bring it to have something that will be hard to take off the field. Great counter to Fire shield for example, or slow CC cards like Plague. So IMO, it should have rather low attack in both versions, with decent HP.
Rage Pots should definitely be considered while trying to balance this card. One Rage pot is basically just increasing its attack by 6, and creature will heal complete damage portion of Rage in the very same turn. Not saying the combo is broken, just that you cannot judge its power level by simply looking at the card alone.
Anyway, I like the mechanic of the card, thumbs up.