I don't doubt that more than a very small amount left in extended contact with the skin could do that especially in a contained location like a boot, where it would not quickly evaporate.
I know when I flipped my ATV, and a moderate amount of fuel soaked my riding pants, it got very uncomfortable, very quickly
, and that wasn't even considering what a SPARK
might have added to the discomfort
.
In most cases when spilled fuel contacts the skin, it is a very small amount, that evaporates, or is otherwise cleaned from the skin reasonably quickly, a larger quantity, for a longer exposure, I am not surprised at the result. But I do Hope he continues to heal quickly, and Appreciate the post, so others can avoid a similar situation.
Doug