Before Lenny and Victor was Chucky. he had been burnt badly. All his hair sizzled in the heat, burnt off or melted unto his own skin.
These were very terrible third degree burns.
Chucky remained on the ground as he spasmed from time to time.
Lenny had indeed controlled the blast well. However, there was more to lenny's blasts. the target had actually not been Chucky, but rather, it had been the Chaos magic inside him.
Yes, Lenny had developed such control of his White flames to such an extent. However, he was still very fresh at using it and that was why Chucky still got very burnt.
Lenny took a look at Chucky, realizing that he was going to be needing a lot more practice if he wanted to use his white flame in such a manner.