What's wrong with my navel piercing ?

I have had it pierced for 7 months and nothing went wrong after 6 months I changes it for the first time and nothing was wrong but a week ago my brother punched my stomach really hard and a bump formed on the left side on the inside big enough to touch the ball and it doesnt hurt unless I touch the middle where the bar goes through the skin Which has never hurt before there is normal crust but no puss what is wrong?? Is it swollen please help!!!!