Foot spots/ sores

Hi all my mum(58) is a type 2 diabetic and have been over the pasted 6 years she is taking Metformin and a few other pills… She experiences a lot of pain in her feet but later there have been little brown /red spots on her feet above her arch…. It is almost like sores but not really…. I think they do not itch but she does not want to scratch them open….

Questions…

1 what are they???

2. how can she treat them????

3. Is there a way of avoiding getting them???

Any advice would be appreciated.

lenny