What Could Painful And Tender Swelling Under The Skin In Buttcheeks Indicate?

Hi, I have a very painful and tender swelling under my skin, the size of a large almond, in my inner lower right buttcheek, not anus. It causes pain when sitting, walking, stretching, and squatting. There is no protrusion externally, although the surface area is hard, and very sensitive/painful. I ve researched images of hemorrhoids and abscess, and my situation doesn t reflect the images, as it is not visible externally. I have had external hemorrhoids before, and the pain is similar, and the build up of mass feels similar, but again no protrusion or signs of thrombosis. No blood in stool, but painful when going. Also Prep H is not helping as it did before. Anyone experience this, or have any ideas what it might be? Please help as it is very painful and concerning. Thank you!