I am just a humble X-ray tech so take my advice with a grain (or less) of salt.
Bursitis is an inflammation of the bursa (the sac in between the joint of the knee that contains synovial fluid) and when this area becomes inflamed it is very difficult to get it to heal because of it's position in the body and the job it is required to do.
I know you have probably already heard this a million times but ibuprofen and ice are probably going to be your best bet (short of a steroid injection).
It always amazes me just how effective these two simple treatments can be when applied rigorously.
"Itis" is inflammation (swelling) and ice and ibuprofen are what reduce swelling the best (for OTC and at home care).
Again, just an X-ray tech, so proceed with caution.
Please follow up with your doctor as a ruptured bursa is much worse than bursitis and could result in a knee replacement.
Best of luck!