My Son 57yrs Old Has A Blister On His Thumb

My son 57yrs old has a blister on his thumb and a bruise in the other arm near the wrist.He is diabetic and his sugar is not under control because of pain he suffers...he is unable to keep to a routine.He had been taking oxynom and then oxy contin for the last one month..now..From Yday he is on Lyrica.
He has been quite ill from Jan this year.He used to be alcoholic. A part of his middle finger was amputated because of an infection he got in Hospital stay.