The Blessing Card does not raise max hp on opponent creatures, only the current hp (meaning, the +3 hp falls off after attacking once)
same for attack, current atk is raised but not max atk. (however, current atk does not get reduced to max atk after attacking. which is a odd inconsistency...)
Please edit the card such that it alters enemy creatures the same way it does own creatures.
Why would I use blessing on opponent creatures in the first place you ask?
Well I have a gravity shield, and am obviously in a bad situation.
Or I have Antimatter in hand and want a greater healing effect.