What is the clear liquid that builds up inside a blister?

Question

so yesterday my finger got pinch-crushed by a door (a small part of the finger got jammed into a door when it closed but not the full finger so it was like a pinch but more painful). the result is what my mum said was a blister. it did go a bit purple but that's gone now.

when i used a pin to drain it because it felt weird when i typed (because of where it is on the finger is bring press on a key or 2). this morning it's filled again. when i first drained it i thought it was puss but the liquid was clear and when i had an infected finger before i had to keep squeezing the puss out of it as directed by my doctor and the pus wasn't clear.

so i am wondering what this clear liquid is and what it is used for?

Answer 1

Is this what you mean?

If so, then yes, it is a blister. Wikipedia entry on blister explains what it is. The clear liquid is blood plasma. It is there to prevent further damage to the tissue and cells, which in your case is the pinch-crushing door. Quoting Wikipedia,

This plasma solution helps new cells divide and grow into new connective tissues and epidermal layers.

The clear fluid will be reabsorbed as new cells develop and the swollen appearance will subside.

Therefore you should not take the liquid out. Just leave it be and it will subside in a few days.