What Causes Painful Lumps On Buttocks?

my wife has 3 lumps just on the outside of her buttcheek, she has never had anything like this before wondering if it could be an infection, a few days before she had a split in her butt crack near the top close to her tail bone, we put polysporin on it and the crack healed up, put then these lumps started, they r swollen and very painful