Prepatellar bursitis that hasn't responded to 3 aspirations + injections. X-ray, MRI and fluid testing give no negative results. Can it pop? Okay?

It's not gunna pop.. Hopefully, the injection that has been put into your knee was a steroid. Just sucking out the fluid is a band-aid -- the needle tip has to be unmoving and the steroid shot exactly into the same bursa space. If that has been done -- all with no trouble detected on testing -- then wrap it, take Motrin, and stay off your knees (kneeling-style).