Hi..
Welcome to HEALTHCARE MAGIC..
I have gone through your query and can understand your concerns..
As per your complain a blood
blister over the but area can be a hair
follicle infection known as
Folliculitis while it can also be a chery angioma that is a malformation of blood vessel while it can also be a
Hematoma secondary to traumatic injury..
At times herpes infection of genitals can also cause similar symptoms.
I would suggest you to
consult a dermatologist and get evaluated and a thorough clinical evaluation can help in diagnosis and treatment can be planned accordingly..
A blood investigation can be advised to confirm the diagnosis..
As of now you can do alternate warm and cool compresses over the blister..
Apply Thrombophob gel..
In case if it does not resolve or if it starts to become painful consult a Dermatologist and get evaluated..
Hope this information helps..
Thanks and regards.
Dr.Honey Nandwani Arora..