Hey,
I had my tongue pierced a few years ago and didn't have any problems with it getting infected. Something about our saliva being able to wash the area out of the mucus .. who knows. Also I tended to use mouth wash pretty regularly after it healed.
I don't know if you use it before it is healed fully if it will sting or not, as I didn't try.
I am sure it will be fine, but like Kylie said if you notice a problem call the doc. Also if you think there is a problem take it out. It will probably close within a few hours. I took mine out just for a break while I ate lunch one day and went to put it in a few hours later (after I had had it or several months) and the hole had already grown up - hence one of the reasons I no longer have it.
Lindsey