nipple piercing pic

Hi girls so I had my nipple pierced before I had my son, when I was pregnant I had to take it out coz my nipples/boobs grew to big and the piercing was uncomfortable after having my son I got it re pierced but it now has that pimple next to it, no matter how many times I pop it, it comes back, pus and blood come out when it's popped! Has anyone else had this or know what has caused it to be like this??? Thanks