<P> 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 ) . </P>
<P> 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 ) . </P>
what is the watery stuff that comes out of wounds
what is the watery stuff that comes out of wounds
lymph serum plasma blood pus
lymph serum plasma blood pus