Hi, thanks for writing to HCM.
From the description it seems that you have developed a Gluteal hematoma
. The sharp pains shooting down the leg could be due to irritation of the sciatic nerve
by the hematoma or due to pressure symptoms of the hematoma on the nerve.
The chances of a hematoma getting infected is much high in Diabetic patients.
Anyway its always better to get an evaluation of your lumbar spine
also to rule out any disc prolapse
which will cause similar symptoms.
Hope this helps