My husband has a quarter-sized red circle on the inside of his left butt cheek. On the right butt check, also toward the inside, he has red patches of skin, one patch, a 1/8 thick line, I noticed this morning. The red circle has been there about a month. He says it does not hurt or itch. He is diabetic, Type II, and sits a lot because his right knee gives him problems walking. What might this be? Thank you.