Take another look at the sentence:
Dangling his legs over the water, Tommy sat
on the pier and cried. Infused with his
great sadness, the tears hit the waves and attracted Marina, a beautiful
mermaid. Popping out of the ocean as
sleek as a seal, Tommy gasped at the sight. While Marina’s tail flopped
against the wood, which was long, scaly, and metallic blue, she asked poor
Tommy the reason for his pain. Tommy explained that he had lost the surfing
championship, which included a scholarship to college. Assessing his set
as clumsy and inelegant, not a single compliment was received from the judges.
After Tommy bemoaned his ineptitude on a surfboard, Marina made a proposal:
She would turn him into a merman with the grace and athleticism of a dolphin!
Wielding ancient ocean secrets with a snap of her fingers, a metallic green
tail replaced Tommy’s legs! Diving into the waves, the tail propelled Tommy
through the strong surf. Ecstatic about his new abilities, the training
and advice Marina offered went unheeded. Refusing to use conditioner, for
example, the sun and salt water soon damaged Tommy’s hair, which became
dry and brittle. A dangerous and foolhardy activity, Tommy also insisted
on head bumping the Great White sharks that he encountered. Putting straws
up his nose and barking like a walrus did not make Tommy popular when he
had dinner with Neptune, Marina’s father. After thoughtlessly scrambling
endangered sea turtle eggs for breakfast, an apology had to be made not
only to Marina but also to the grieving reptile mother. One day out on a
swim, Tommy drank a root beer and tossed the empty plastic bottle in the
water. Polluting the ocean so carelessly was the last clam shell for Marina.
With an angry snap of her fingers, she replaced Tommy’s tail with two human
legs. Sinking under the waves, Tommy’s legs finally kicked him to the surface
where he gulped a much needed breath of air. Saying a curt goodbye, Marina’s
tail slapped the surface dismissively as she dove into the ocean depths.
While swimming the mile back to shore as a regular human being, Tommy regretted
the gift that he had squandered.
No error exists. Infused with his great sadness, a participle phrase, comes right before tears. Since tears are tainted with this emotion, the modifier is in the right place.