Well, I had my Tongue pierced last Thursday and I found that the most uncomfortable part of it all was trying to eat and talk, as it would hurt my Tongue a little. I rinsed my mouth out with an alcohol free mouthwash everything I ate and drank anything that wasn't water or ice. For the first 1-3 days I was living off mashed potato, ice cream, jelly, and ice cold water, but on day 4 i managed to eat some toast. My swelling went down completely after 6 days and I had my bar changed to a smaller size yesterday and now I love it! It's definitely worth the few days of not being able to eat or talk much. Also, after about 3-4 days you may notice a bit of puss coming out of the holes. If its white then its normal and its just your Tongue getting used to the bar being there and to clean the wound. I also experienced a bit of bleeding over night, that's also normal as long as its not too much blood! If you have any problems or are worried about anything be sure to ring your doctor or piercer and they will help you out. Having an infection on your Tongue wouldn't be very nice - yuck!
Oh yeah, more about the pain and swelling - I didn't take any pain killers as I wasn't having that much pain, but make sure you're careful when you eat as you may bite down on the barbell and damage your teeth and it may also be a bit painful when you do eat. Same with talking, try to keep talking to a minimum as I found it hurt when I spoke. I don't think my Tongue swelled too much, although I woke up one morning with teeth marks in my Tongue because my Tongue was pushing against my teeth! Haha.
Anyway, hope I helped X