You're close. You probably want to put all your strings into an array, then use the reverse of split, join to put your '&' into place. Continuing from your code:

my @strings;
foreach $keyword (@keywords){
    $wordnum++;
    push @strings, "keyword_$wordnum=$keyword";
}
my $string = join '&', @strings;
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Dr. Michael K. Neylon - mneylon-pm@masemware.com || "You've left the lens cap of your mind on again, Pinky" - The Brain
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