A little part of my gum is slightly swollen, what's up?

Many possibilities: The swelling can be from a gum infection, trauma, a burn from hot cheese( known as pizza burn), packing food between teeth(often a popcorn kernel), or a tooth is abscessing. There are also oral pathology possibilities that will cause swollen gums. See your dentist to identify what is the cause of the swollen gums.

Possibly infection: There may be an inflammation or infection present. You should see a dentist to have it evaluated.