I have this lump on my belly were my belly bar was laid how would I get rid of it and would I be safe to get it done again

That may just be a scar? A piercer should be able to tell you whether or not its safe for a repierce

It sounds like scar tissue, how long have you had your belly bar taken out? Usually this will fade with time, and it could be worthwhile getting something such as bio oil and massaging it in daily. The more moisturised you keep an area of scar tissue, the quicker it will start to heal.

You may be able to get your navel re-pierced, that will depend on where your first piercing was. My girlfriend got hers re-pierced and the piercer just has to go in a little further behind the original piercing. You will need to check this out with your piercer though, to ensure that the original placement will allow for this.

Good luck