What are the blister like very itchy bleeding sores on front of my legs

I have blister like spots on my legs.  They itch badly.  After scratching they leave a big round hole in my leg, bleed badly and then scab over and become very red around the scab.  If I remove the scab they bleed for a minute or so.  The skin under the scab is very raw looking.  I am diabetic and this has been going on for almost a year now and the Dr.  seems unconcerned.  Just tells me it is caused by my diabetes being out of control and put antibiotic ointment on it from otc.  I find this hard to believe that it can go on a year and the Dr just shrug it off.