If it's impacted get it sorted. I left mine for years and ended up with a huge chunk of one of them falling off, massive decay and a LOT of pain. If you have to have it out, which is likely because wisdom teeth either grow through straight or are total pains in the backside, and get progressively worse, and are worried about it, you can be sedated, or even knocked out (although this means you would have to go to a hospital as dental surgeries can't knock you out anymore). Really depends how bad you are with dentists! I have panic attacks with check ups so they didn't even suggest me having (all four) of mine removed at the surgery, and referred me to the hospital.
Keep an eye on it - if the area around the gum because really swollen or white in colour you could have an infection which is easy enough to get rid of - the dentist would be able to sort it for you.