Half of my wisdom tooth came through, now the other half of the gum is swollen. is this normal?

Infection : It is easy to get food debris stuck under the tissue around the wisdom tooth because you cannot clean it. This causes an infection that needs to be treated by a dentist. The dentist may recommend extraction of the wisdom tooth. For now clean as well as you can, rinse with salt water, take ibuprophen if you can, and call your dentist asap.

Common yes, : Normal--no. You are describing acute pericoronitis of a partially impacted tooth. Same rule as always applies: if you can clean it--the whole tooth--you can keep it. If you can't, get it out when you are young and an heal quickly. If you are over age 25, have it removed when infected or affecting tooth in front of it.

Pericoronitis: This is pericoronitis. An infection. You need otc pain meds, salline rinses see an oral surgeon for antibiotics and an evaluation to have the tooth removed.