They swell a tad when you get them done professionally, so if you mess it up, (which you probably will, no offense) you're going to look like you got punched in the mouth. Save yourself the uncomfort and get it done by someone who knows what they're doing. :)
When done non-professionally there's a much larger risk of infection which could lead to a lot of swelling and not to mention puss as well. Hella attractive.