I've had my belly piercing for 8 months now and it was going good in the first month but then I got this big purple bubble on the right side of my piercing hole and I use tea tree oil in the night and it goes down a little but then it gets bigger when I go in the water or take a shower so I would like to know what it is and how I can get rid if it. PLEASE HELP ME

You see a doctor because it sounds like an infection.

Thank you , even if the bubble is on the side of my piercing hole it's still infected ? How do I cure an infection ?

How to cure an infection? After the doctor verifies the problem, he will probably prescribe you antibiotics.