The night before the big school dance, Pearl gets a barnacle on her face. After requesting expensive treatment to get rid of the blemish, Mr. Krabs refuses and asks SpongeBob to help Pearl remove the barnacle. He tries prying the barnacle out with his spatula, then a shovel, then a jackhammer, all to no avail. Then, when Pearl washes her face with soap, more barnacles sprouted up. Thinking all hope is lost, she locks herself in the restroom and cries violently. SpongeBob then decides to simply hide the barnacles under a layer of facial cream, which ends up making Pearl's face look severely deformed and causing her to be unable to talk. Finally, Pearl asks SpongeBob to get her more soap from the basement, where he finds Mr. Krabs producing the house's soap. Mr. Krabs explains to SpongeBob that he make all of his soap out of leftover Krabby Patties. Pearl overhears this and, realizing that she's been washing her face with grease, screams at her father and gives up trying to remove the barnacles. SpongeBob, inspired by something she said, resolves to cover up the barnacles with Mr. Krabs' precious jewels. Pearl's friends are dazzled by her sparkling face, and they happily depart for the school dance. Mr. Krabs, furious that Pearl is wearing his diamonds, desperately sprints after her, as the episode ends.
This episode is very similar to a comic strip "Barnacles" when SpongeBob sleeps through his day off and gets covered in barnacles.
In this episode, it is revealed that SpongeBob knows how to swim. In "SpongeGuard on Duty," SpongeBob does not know how to swim, but he probably had learned swimming because at the end of that episode, Larry teaches Patrick and him to swim. So, this episode probably takes place after "SpongeGuard on Duty."