I have a 3 yr old long haired daschund that is over weight and currently has some sort of an external skin scabs that first were puss, abcess then they became black discoloration and hardened skin, this is around the abdomen area. Also, he's been vomitting and shivering for awhile. I took him for a check up but the vet said that he might need antibiotics or it could be allergies or protozoa but didn't give much information, only that it is possibly a secondary infection. He seemed not too worried. I am very worried and don't know what it is and how to treat it or atleast discover possible reasons for it.
Optional Information:
Age: 3; Male; Breed: Dog/ Long haired daschund
Already Tried:
Previous antibiotics.