system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What is going on when just one taste bud on the tongue becomes swollen and painful?
gpt
It's called a sweet spot (papilitis). Caused by different things for different people, but usually after eating very sugary or acidic foods. 

Pineapple for me, being very sweet and very acidic, always pisses off at least one tastebud, and it gets exactly as you describe: A single tastebud very swollen and painful.