Went to my GP again last week who has referred me onto Orthopaedics with a possible baker's cyst, although he said I was a bit young for it (i'm 18). Today though, I've had an awful burning ache in my knee and the lump at the back of it seems to have decreased in size a little bit. Can a baker's cyst do that? or if it does rupture, does it disappear completely? help, i'm actually in a lot of pain here but it'll probably be a long time before I actually get to see a doctor about this pain.