We should probably clarify what it means to 'get better'.
As Serath points out, the actual physical prolapse and/or structure of the valve does not tend to change over time. This means that it won't (likely) just go away, but it also means that it does not tend to get worse over time.
However, since MVPS is really a myriad of symptoms that are not necessarily tied to the actual valve (it just seems like it), then the answer is YES, it can 'get better'.
In other words, yes, you can feel better. You can go months or years without any problems. But this does not mean the structural problems (if there are any) are necessarily going away.
Remember that we are talking about a syndrome when we speak of MVPS, which is not the same as just plain MVP & MVR.