Hi,

I got my tongue pierced 4 days ago and now I'm kind of regretting it. As I didn't do any research into it, it was just a spur of the moment thing.
I was just wondering if I were to take in out now, would the hole go away and completely heal?
Or if I took it out, is there a greater risk of infection as the hole is exposed?
It is still a little bit swollen but not as much and I am still having difficulty speaking which is worrying me, is this normal?

Yes, the hole will go away eventually, but it will probably take some time. Lucky for you the tongue heals really quickly by comparison to other parts of the body. If you take it out you're at the same risk for infection as with it in- maybe even safer with out it as some bacterias like to colonize metal.
My advice to avoid infection would be to swish your mouth with salt water or hydrogen peroxide at least once a day and to make sure you brush your teeth to keep germs down. Honestly both of these things will probably hurt, but it will help it heal faster and prevent bacteria from invading.

Most people who have there tongues pierced have a severe lisp even after years with the piercing. And you just rammed something through your tongue. So yes difficulty talking and the fact that it's still swollen are fairly normal. If you do decide to keep it in make sure you keep it clean otherwise it will really get swollen and hurt.