Take a look at the original sentence again:
After the thunderstorm, Teresa splashed through the puddles left on the
street, she enjoyed feeling the cool rainwater
on her hot feet.
You wanted to fix it this way:
After the thunderstorm, Teresa splashed through the puddles left on the
street she enjoyed feeling the cool rainwater
on her hot feet.
To delete the comma between street and she would cause an equally bad problem, a fused sentence. A fused sentence occurs when you have two main clauses joined with no punctuation whatsoever. Teresa splashed through the puddles left on the street is the first main clause. She enjoyed feeling the cool rainwater on her hot feet is the second main clause. The spot between street and she needs a stronger break than blank space.
You might want to consult the rules for fixing comma splices and fused sentences.
Go back to the sentence to try again.