Describe your what causes the ignition switch to blow on a 1993 Lincoln Problem

I wouldn't discribe a well used & well worn 18 year
old switch, as blown

Was there a high current load on some of the
ignition switch wires over many years,who knows

Just change it & address what lead you to the switch

There may be other things that need attention as well,
& the switch is just one part of a system filled with problems