Prepatellar bursitis, infrapatellar bursitis, and superficial infrapatellar bursitis are all fairly transient. This means they can appear quickly out of nowhere, but also dissipate quickly if proper treatment is applied. This type of bursitis will often come on strong for 2-3 days but will return to normal within a week. Typically, the first few days are particularly bad (redness, swelling, bruising sensation, stiffness). This usually subsides after 48 hours. In less than a week, the knee is typically back to normal (sans a little swelling if you retain a lot of fluid).