Is there a difference between mitral valve prolapse and mitral regurgitation?

Yes: One can have either without the other. Prolapsed mitral valve leaflets could leak. Leaking mitral valves could be prolapse. However, one can have prolapse and no regurgitation or regurgitation and no prolapse.

Yes: Mitral valve prop lapse is a description of how the valves close. If one or both of the leaflets bow up into the left atrium that is prolapse. Not all prolapsing valves leak. Mitral regurge is when the blood leaks backwards into the left atrium. Some people with prolapse have leaking valves. But also not all leaking valves have prolapse. So they can be related but are not the same thing.