My mother developed a strange lesion on her hill

[RainaNI]

The entire hill looks like a bullae, filled with blood. The skin around is red, some places with whitish, hard on palpation blotches, that later became blue of color. No pain, or itchiness. It is  localised, no other places on the body are involved, does not spread or grow. PCP does not have a clue. My mother
is still fighting a flu. Cough  congested nose, low grade fever. Last day on Z pack. She has type 2 diabetes, treated with insulin injections and diet. No history of an autoimmune disorders.