White Lump Inside Cheek My Boyfriend Has A Lump Inside His Left Butt Cheek...?

My boyfriend has a lump inside his left butt cheek...? - white lump inside cheek

Now I know this is TMI, but I'm really worried for him reallyyyy. It is literally black when the tumor is. It is not white or red. It belongs to the skin a little and it hurts to sit. He says he has been for some time, and refuses to seek medical care. I am very worried for him. Who knows what could that be?