I recently went & got my tongue pierced on 8/8/14 to be exact & now the ball has formed deep dent on my tongue almost like a pocket around the top ball & I'm concerned my bar may be too short . What should I do ? & my tongue is also still swollen so should I give it time for the swelling to go down & see what happens or immediately get a longer bar ?

Wait for the swelling to go down and then decide. The problem is disturbing the healing process by replacing the barbell. Keep it as clean as possible and keep an eye out for infection.

Okay & also I'm concerned that the swelling may not go down because of the pressure from the top ball on my tongue causing it to stay swollen .

It shouldn't. When you look at what you have actually done, caused trauma to your tongue by inserting metal through it, the swelling makes sense, and it will go down. Just need to give it a little time and make sure that it remains clean and uninfected. If it doesn't go down in a week or two or if you notice obvious signs of infection then go see a doctor.

Okay , thank you so much for your help !