 [ Symptoms ] i have a cluster of blisters on the top part of my butt crack what is it [ Disease ] unfortunately this condition can only be diagnosed with a physical exam we can not tell you what this is over the internet any number of conditions can cause the symptoms you are describing it could be something simple like a boil or it could be something more serious like a pilonidal cyst the only way to know for sure is to make an appointment with your health care provider and get examined i wish you all the best