Again, consult perldoc perle. Using a character class containing only a space is one of many ways to do this.

my $pattern = qr(i[ ]*am[ ]*using[ ]*per);

And, when you post code, you'll help yourself by first checking that code by:

use strict;
use warnings
[download]

and then perl -c scriptname.

The apparent failure to do the above; the apparent failure to take several pieces of advice in previous replies; and the missing semi-colons suggest that you don't care so much about learning from the wisdom of the Monks as about using them to write your code.