What Causes Cluster Of Bumps On Buttocks And Anal Area?

I ve had this small collection of bumps on the inside of my butt cheek, near my anus, for 7 days. They hurt, are itchy sometimes & annoying. I ve tried antibiotic ointment & started lanolin 2 days ago. They re still there & not getting less painful. I ve never had this. They haven t spread anywhere else on my skin.