From your symptoms,it looks like a boil on the buttocks. A boil, also referred to as a skin abscess, is a localized infection deep in the skin. A boil generally starts as a reddened, tender area. Over time, the area becomes firm and hard. Eventually, the center of the abscess softens and becomes filled with pus. Finally, the pus "forms a head," which can be surgically opened or spontaneously drain out through the surface of the skin.
Boil on buttocks is usually due to plugged sweat glands that become infected or by an ingrown hair.
Apply warm compresses on the boil and keep the area clean.Drainage of the boil is done only when it becomes soft and forms a head.Take some over the counter pain reliever and consult a doctor for examination and antibiotics prescription.If there are recurrent boils,then pls get your blood sugar levels estimated.
Hope it helps.Take care and pls do keep us posted if you have any additional queries.
well its not A boil
its a rash im thinking some sort of fungus thing
maybe even like a yeast infection if thats possible