You don't tell us why which leaves plenty of room for guessing. If you don't need to use a regex you can get a count of word use like this:

use strict;
use warnings;

my $text = "and him him lad has him done and john has has";
my %words;

++$words{$_} for split /\s+/, $text;
print "$_: $words{$_}\n" for sort keys %words;
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Prints:

and: 2
done: 1
has: 3
him: 3
john: 1
lad: 1
[download]

If that's not helpful for your immediate problem you might like to give us some more context.