We can use split with a regex to get the second last string 1 and then apply another regex to get the last three characters in the second last string1

#!/usr/bin/perl


use strict;

my $string = "KLEWREGREG-----REGREGEWD....-EWGREGERABCSHRT..----...XFG
+HWW....----....TRYU";

my @array = split ("[.-]+",$string);

my $interested = $array[$#array-1];

print $1 if ( $interested =~ m/([a-zA-Z]{3}$)/);


Output :
HWW
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