Best guess I had.
Now I got nuttin’
My best guess is the kid was vaping, bringing the e-cig up to his mouth, and fell, face first, hitting the e-cig on the ground, which drove the mouth piece of the e-cig into his mandible just below where his teeth erupt from the jaw, one of the weaker areas of the jaw. This cracked the jaw vertically and shattered the mandible in that area. In addition, it broke the e-cig tank, splashing hot juice on his lip, accounting for the minor lip burn. In the fall, the battery may have ruptured striking the ground. . .
Someone got the idea they could sue the e-cigarette maker by claiming the e-cig exploded, causing his injuries. But his injuries are inconsistent with such a scenario. Alternately, he also may have been drinking, and falling down drunk, which caused him to fall, and the e-cig story is what he told his parents to cover up what actually happened.