You are, in essence, bleeding internally. Since this has being going on for months you have a wound which is not healing - more or less a broken blood vessel which is 'leaking' under the skin and is not being repaired. This is most likely due to a disease, an infection unless the spot is being repeatedly injured which other than your popping it and you shouldn't, unless its hindering movement or too painful, then it needs to be seen by a health professional to pop it in a manner which would greatly reduce the risk of infection. There are several skin disorders on the list: * Impetigo: A skin disorder caused by bacterial infection and characterized by crusting skin lesions. most commonly in children, but some adults can get it - considered rare in the western world, but not too uncommon in poverty stricken areas of the world. * Incontinentia pigmenti: A skin condition passed down through families that causes unusual blistering and changes in skin color. The condition is most often seen in females. When it occurs in males, it can be deadly. however it is usually detected within two week after being born. Still a few very rare cases have 'shown up' in later adulthood. * Pemphigus vulgaris: An autoimmune skin disorder characterized by blistering of the skin and mucous membrane. Although rare, Pemphigus may be a side effect of certain blood pressure medications (ACE inhibitors) or chelating agents (medications, such as penicillamine, that remove certain materials from the blood). * Herpes - either/and/or both can spread beyond their normal range on rare occasions. There is also some recent research related to blisters and the earmarks of some cancers. Have a I scared you? Sorry that was not my intention. My intention was to over inform you, to let you see just how many different things COULD be causing this and hopefully getting you motivated to see a doctor about a blister that will not go away. If your not seeing a doctor due to lack of insurance, most states/counties/parishes have "Free Clinics" which work on sliding scale or if you are indigent will pay your way - ergo the free part. I can not stress enough that when a condition lasts for months it is very serious and needs medical attention, not advice from a public board. It is most probable that after the initial injury you got it infected causing the blood vessel(s) affected to continue to leak blood - more or less you most likely need the correct antibiotics (not what you think are correct) and lancing and possibly now even cauterization to stop the bleeding.