don't know what it is...

[xray86]

i have what looks like blood blisters on my thigh and lower leg. it swells up and is very hard underneath and very painful. when it breaks it's full of blood and after the blood is gone it looks like a punture wound. is it a blister, cyst, or something worse?

[BhumikaMD]

'If a blister bursts, don't peel off the dead skin on top of the blister. Gently press the area to get rid of all the fluid inside, and then cover the blister and the area around it with a dry, sterile dressing to protect it from infection until it heals.

Blood blisters should also be left to heal naturally. As with other blisters, if a blood blister bursts it is important to keep the area clean and dry, and protect it with a sterile dressing to prevent infection.

Blood blisters are often painful, and you may wish to apply an ice pack to the area immediately after the injury that caused it. You should apply the ice pack for between 10 and 30 minutes. The ice should not touch your skin directly as this may cause a cold burn, so place a towel over the injured part first.

Even when popped as described above, a blister can become infected, Staph aureus infections being most common. Blisters that have become infected can be treated with antibiotics prescribed by your GP. '

http://en.wikipedia.org/wiki/Blister

It would be best to consult a doctor if it does not resolve on its own in a few days.

Let us know if you need any other information.

Regards.