A photograph would do wonders to more concretely answering your question.
Photographs and an actual consultation might allow one to be more definitive in answering your questions. It can sometimes be that the ptosis was present but more noticeable after the double fold surgery. Significant bruising associated with the surgery can cause ptosis as can persistent swelling. The reality is that it is amazing that more of use don't develop upper eyelid ptosis. The reason is that the tendon that raises the upper eyelid is held in place by loose tissue. The presence of ptosis makes it possible to correct the high crease. To answer your question about how easy is this to correct, it very much depends on what is found at the time of the consultation. Your potential surgeon should be able to answer these questions based on a very through assessment.