The whole thing exploded in a flash of blue light and energy.
He wasn't able to get away fast enough so the explosion occurred some distance from his face. He truly got a face full of the flash. However, he was fine.
The explosion wasn't enough to harm him even if it had struck him in the face. The worst that it could have done was burn all of his hair and make him bald.
He had experienced that before, which was why he had activated an energy barrier once he sensed the brewing violent energy. So even if he hadn't stepped back, his long green hair would have been safe.
To top things off, even if he had been injured, he would have healed it easily as seen by the rapid healing of the injuries in the palm of his hand from when he was pierced by the roots of the armament. Very soon, no one would be able to tell that he was ever injured.
He stood where he was, scratching his chin. He was thinking about what went wrong and how to solve it.