Q: Context: A blister is a small pocket of body fluid (lymph, serum, plasma, blood, or pus) within the upper layers of the skin, typically caused by forceful rubbing (friction), burning, freezing, chemical exposure or infection. Most blisters are filled with a clear fluid, either serum or plasma. However, blisters can be filled with blood (known as "blood blisters") or with pus (if they become infected).

Question: what's the fluid that comes out of blisters? Let's give stream of consciousness first:
To answer the question, consider the following: A blister is a small pocket of body fluid (lymph, serum, plasma, blood, or pus) within the upper layers of the skin, typically caused by forceful rubbing (friction), burning, freezing, chemical exposure or infection. Therefore, the final answer is lymph , serum , plasma , blood , or pus.