I would wait to do any hardware work yet. Just fly it another 5-10 hours or so, LOP preferably, then do another compression check.
My friends IO520BA had low compression when he bought it used, then the next compression check was higher and better just because it got rid of all the ROP crud.
Obviously LOP won't get rid of a real mechanical problem like a burnt valve. No leaks via the valves should be allowed.